We talk about heartache when love is lost. We talk about hearts fluttering when love is found. We send heart emojis and heart-shaped Valentine's and make hand hearts on Instagram. We're heart-obsessed.

It was only a matter of time before someone harnessed that obsession, added a little science, and tied it to another popular obsession: health and fitness. That someone is Once, a new dating app that uses your heart rate to determine your heart's mate.

Once, which can now be integrated with Fitbit and Android Wear, shows users a single potential suitor each day. The matches are curated by actual human matchmakers, who work their magic by reviewing your profile and the profiles of people you've liked in the past. When you're given your daily match, you have 24 hours to make a move before the match expires.

OkCupid has built a reptuation as one of the more open-minded dating services available for singles. In their latest progressive move, the site is adding a feature designed to help users explore nonmonogamy.

The new setting became available for some beta users last December and rolled out site-wide in Januray 2016. Polyamorous daters who are listed as “seeing someone,” “married,” or “in an open relationship” can now link their profiles with their partners' profiles and search for new additions to their relationship.

The decision to add the option for polyamorous users comes after OkCupid noticed an uptick in interest in nonmonogamous relationships. According to the company’s data, 42% of its users would consider dating someone who is already involved in an open or poly relationship. Another 24% say they are “seriously interested” in group sex. Combined, reports The Atlantic, those two numbers represent increases of 8 percentage points from five years ago.

Perhaps more surprisingly, the number of OkCupid users who say they are solely committed to monogamy has fallen to a minority of all users: 44%, down from 56% in 2010.

The trend on OkCupid is reflective of a larger trend throughout the United States. Psychology Today reported in 2014 that "sexually non-monogamous couples in the United States number in the millions." Surveys suggest that 4 to 5 percent of Americans are now involved in polyamorous relationships.

This isn't the first time OkCupid has made headlines for its forward-thinking take on online dating. The site added an “open relationship” option back in 2014. Last year, it increased the number of genders it recognizes to 22. Tinder and Match.com, also owned by OkCupid parent company Match Group, do not yet have plans to add a similar feature for nonmonogamous users.

Outside of Match Group, OkCupid remains a trendsetter. Though specialized dating sites for polyamorous people were already available, this seems to be the first time a mainstream online dating service has offered a feature for nonmonogamous partners. In the past, poly couples resorted to creating confusing joint profiles or describing their arrangement in their bios.

Jimena Almendares, OkCupid’s chief product officer, told The Atlantic the company isn't trying to make a statement – it's merely following the numbers and giving users the tools they need to find the relationships they want.

“Finding your partner is very important,” she said, “you should have the option to express specifically and exactly who you are and what you need.”

For more information on this dating service please read our review of OkCupid.

The business of online dating continues to grow, as more apps enter the market and compete for funding from investors ready to cash in on the next Tinder. The latest financial news in the industry involves popular gay dating app Grindr, who just announced that Chinese online gaming titan Beijing Kunlun Tech has taken a “majority investment” in their app.

According to The New York Times, Beijing Kunlun’s stake in the company will be about 60%, with the remainder to be owned by Grindr employees and Joel Simkhai, the company's founder. The valuation of Grindr seems to be about $155 million according to the same article, although the actual amount invested was not disclosed.

Interestingly, Grindr had not raised capital from outside investors prior to their deal with Beijing Kunlun. The company was started and funded by Simkhai himself, who began with only a few thousand dollars. He grew the company and the brand: according to PC Magazine, the average user spends up to 54 minutes a day on the app – a figure that exceeds Facebook’s 42 minutes and Instagram’s 21 minutes.

According to leaked documents back in August, Grindr predicted pulling in about $38 million for 2015.

According to Financial Review, Carter McJunkin, chief operating officer of Grindr said in an interview: "We have users in every country in the world, but in order to get to the next phase of our business and grow faster, we needed a partner," McJunkin added that the relationship made sense for Grindr because of Beijing Kunlun's digital expertise, and because the company agreed to let Grindr's founders continue its operating structure and retain its current team.

Beijing Kulun saw Grindr as a good opportunity to expand beyond its core gaming focus, into more of an overall “lifestyle” brand. 

It’s interesting to note that Beijing Kunlun’s choice to purchase stake in a gay dating app seems incongruous, since homosexuality is still a taboo subject in China, and many gay people face widespread discrimination. It is not clear if Grindr intends to expand its business into the Chinese market, but there would be social stigma to overcome.

Beijing Kulun might see Grindr as a sound investment above all, despite its target market. Or perhaps they are paving the way for other Chinese investors to expand and reach out to invest in more diverse, successful brands outside of China. "We have been very impressed by Grindr's progress to date and are extremely excited about the future of the company," Yahui Zhou, chairman of Kunlun, said in a statement. "We will continue to seek out and invest in high-quality technology companies led by top-tier management across the globe.” For more information on this gay dating app you can check our our Grindr Topic.

Friends Reunited won’t be available to message, post and keep in touch anymore. The once-popular social site, founded in 2000, was left in the dust by rivals such as MySpace and later, to a larger extent, Facebook.

Friends Reunited has a turbulent history. At one point a tech darling after quickly gaining three million subscribers in 2003, it was sold to ITV in 2005 for 125 million pounds, or about $208 million US. At its peak, 23 million users were on Friends Reunited.

But what the company didn’t intend was that employers would begin to use the service to check on potential and current employees, gauging what they said on social media as opposed to how they conducted themselves at work. It led to businesses using the site as a way to spy on employees, gathering information such as whether an employee was looking for another job, what they were saying about co-workers, or what interviewees and potential employees were saying online that could be potentially harmful.

At one stage, according to UK newspaper The Telegraph, Friends Reunited was blamed for a spike in the divorce rate on the grounds it encouraged classroom sweethearts to rekindle romances.

Instead of a positive, uplifting social experience where people felt secure to engage and share, the company found its platform being used as a way to spy on people for bad behavior. Naturally, users over time stopped posting and using the service. Membership dropped, especially when Facebook entered the picture a couple of years later. While Facebook continued to gain users, Friends Reunited found itself floundering.

The company was sold yet again in 2009 to DC Thompson for only 25 million pounds, and had only a fraction of its user base still active on the site. In 2012, the company decided to do a reboot and rebrand itself “Memory Box,” hoping to take on Facebook’s rapid growth. Memory Box did not succeed.

In 2014, DC Thompson offered the platform back to the original founder of Friends Reunited Steve Pankhurst, who thought he could restart the fledgling website. But in an announcement made on self-publishing platform Medium, Pankhurst announced its closure in January.

He wrote on Medium: "The first part of our plan was to put Friends Reunited back to make it more like the original site  --  that is, listing your schools and memories of your school days." However, this didn't really happen.

Pankhurst is now working on a new social media site called Liife, which allows you to upload photos and mark and share them with friends to identify significant “moments,” like trips, awards ceremonies or graduations. He said the new site would in no way replace Friends Reunited.

The related service Friends Reunited Dating still appears to be in operation and is not affected by the closing of the social service Friends Reunited. For more information on dating site please read our review of Friends Reunited Dating.

The 2015 Dating Sites Reviews Single's Choice Award poll was closed for voting at the end of 2015. In the 3 months it was open to voting the poll received 459 votes which is exactly 100 more than last year (which is a little weird). This poll is design to find out what our visitors feel is the best dating service. For this award we are looking at the top free dating site and/or app. The top 8 free dating services where picked by the Editor's to be contenders. In order for these dating services to be selected they needed to meet a number of criteria. This includes having a review on Dating Sites Reviews, having the core features of the service being free (including, profiles, searching, and messages), and being a service which is popular with our visitors.

The recipient of the 2015 Single's Choice Award for a Free Dating Site is Plenty Of Fish (POF). This is the seventh straight year in a row that POF.com has won this award. In 2015 POF received 134 votes which is 29 percent of the total votes cast. POF came in a little stronger this year as it received 4 percent more of the vote compared to last year.

Here are the final results of the poll:

1. Plenty Of Fish (POF)
2. OkCupid
3. Tinder
4. Meetup
5. DateHookUp.com
6. ChristianDatingforFree.com
7. Mingle 2
8. Craigslist

The top 3 dating services received 70 percent of all votes. POF received 4% more votes than OkCupid which came in second place at 24.8 percent. Rounding out the top 3 was Tinder which had 16 percent of the votes which is 75 votes in total.

Read our review of PlentyOfFish.com for more information about this online dating service or visit Plenty of Fish directly.

Online dating is big business after the holidays. In fact, user activity remains consistently high until Valentine’s Day, according to reports from online dating veteran websites like Match.

But it’s also a huge time for dating apps, especially Tinder – who had its biggest growth day in its history. On Sunday January 3rd, Tinder execs revealed that the app experienced the most downloads and the most growth of active users in a single day - ever. (Coincidentally, most online dating sites report that their biggest, busiest day of the year is the Sunday after New Year’s, when people are faced with the end of holiday revelry and the return to work.)

Needless to say, Tinder must have seen this spike coming and decided to take advantage with a new feature, which came in the form of a push notification. The notification alerted users when there was 2x to 3x higher rate of matches in their local area. It said:

Wow! Tinder is on fire in your area! Chances of a match are 3X higher right now (flame emoji)

The push notification was an interesting choice for Tinder execs to make, since the app prides itself specifically on not sending unwanted messages to its users, keeping the interaction as seamless as possible.

Tinder CEO Sean Rad looks at the feature as a win-win for users. “When there is a spike in engagement on the platform, we want to let users know so that they can take advantage of that moment,” Rad told news website TechCrunch.

The match rate is the number of swipes it takes to get to a match. When there is more engagement, the likelihood of matching with someone goes up. In a way, it’s a self-fulfilling prophecy. If you tell someone that the match rate is 2-3 times higher, then likely they will keep swiping (engaging) until they get a match.

“The most fascinating thing about this type of notification is that, by notifying users when those peak moments are happening, it increases the overall success rate for our users,” Rad told news website Tech Crunch. “It has a compounding effect and produces even more activity.”

The match alert is the latest in a series of moves Tinder has made to overcome its hook-up reputation and concentrate on more long-term matches. The company has also been sharing stories and photos of happy couples who met on Tinder, including a tweet from a couple on their wedding day, hoping to show proof that the app is helpful for finding long-term love.

Tinder faces competition from new services like Bumble, which lets the women call the shots first, and Coffee Meets Bagel, which provides one match a day to make sure people aren’t just mindlessly swiping. For more on this dating app, please read our review of Tinder.