Facebook (META -5.68%) has long been inadvertently a dating site. The social network has always been a place for old flames to reconnect, people to confess past crushes, and for semi-strangers to bond over a shared love of funny cat videos. Now however Facebook is taking things a step further and putting a toe into the online dating market by adding a button that allows site visitors to ask people without a declared relationship status whether they are single. The feature is only available for some users in a limited test. 

Clicking on the "Ask" brings up a dialogue box with the text, "Let (your friend) know why you're asking for (his/her) relationship status." 

"This feature provides an easy way for friends to ask you for information that's not already on your profile," Facebook spokeswoman MoMo Zhou told CNN. "For example, a friend could ask where you work or for your hometown. If you choose to answer, this information is then added to your profile. By default, only you and your friend can see it, and you also have the option of sharing it with others, too."

That explanation specifically avoids acknowledging that the "Ask" button allows a Facebook-sanctioned way to inquire whether someone is single. Facebook has never embraced its role as a site that facilitates hookups the way products like SnapChat and, in a more illicit sense, Craigslist have. 

How big is the online dating market?

While Facebook has unofficially and perhaps unintentionally led to countless relationships, affairs, and other romantic engagements, allowing customers to inquire about other members' relationship status is a step toward entering the online dating space. Facebook may never directly compete with eHarmony or Match.com, but if it offers subtle tools that allow for people to meet (or reconnect) for possible romantic relationships, it could siphon business away from traditional dating sites while growing the category. 

Compared to Facebook's nearly $8 billion in 2013 revenue the overall size of the online dating market, which researcher IBISWorld pegs around $2 billion, is relatively small.   Still Facebook already has an enormous global customer base so it can make money by facilitating meeting and eventually dating without the expense of customer acquisition. Facebook can also be a subtle player in online dating, bringing people together without the stigma associated with online dating.

Unlike many dating sites that charge for membership, if Facebook chooses to play an active part in helping its members find love connections it can do so in an ad-supported fashion. The "Ask" button is a small step in that direction but it's one that could be the equivalent of a social media pickup line. It's also an interaction with its service that Facebook can easily monetize.

Facebook users "Asked" about their relationship status are also prompted to update it publicly (though they can choose to not do so). This is good for Facebook too as relationship status allows the company to sell targeted ads. The more info Facebook gathers on its pool of users the more it can charge advertisers to reach exactly the people they are looking for. Is your product aimed at married Star Wars fans between ages 35 and 42? Facebook can deliver exactly those people, which makes finding clever ways to encourage people to complete their profiles important.

Small dollars, big impact

Though $2 billion is not that impressive a number, online dating has clearly affected how people meet and eventually get married.

"Of 19,000 couples married between 2005 and 2012, more than a third met through an online dating site, according to a study in last May's Proceedings of the National Academy of Sciences," The Fiscal Times reported, adding that, "last December, more than 1 in 10 American adults visited dating sites, spending more than an hour a day there on average, according to Market research company Nielsen." 

With this many people affected, it seems likely that Facebook could find ways to monetize that existing dating sites are not able to do.

It's just a small step

Facebook allowing users to inquire easily about a friend's (and friend is being used in the loosely defined social media way) relationship status is not the same as the site launching a dating service. It may however be a prelude to the company more fully entering the dating space. The social media giant has the ability to connect its users based on their interests. In real life -- back before the Internet replaced so much person-to-person interaction -- couples often met through their mutual interests. If you liked thrash metal and you kept seeing the same girl at concerts, well, there's no guarantee she will like you but it's clear you would have something to talk about on your first date (though you may need to talk loudly due to all that thrash metal). Facebook can make those connections without requiring people to do something as inelegant as actually leaving the house.

It's hard to know if Facebook will make a more formal entree into online dating but even this simple move is likely to result in increased revenue for the social media company and a new round of people getting together because of the service.