Facebook’s annual F8 developer event kicked off today and the company has made a number of pretty big announcements. Among them was the announcement of plans to create a dating platform directly in its mobile applications. Investors in Match Group, which owns many online dating services including Tinder and Match.com, have not taken very well. As of this writing, the company’s shares have fallen by more than 20%.

MTCH took a pretty big hit today.

In addition to Tinder and Match.com, Match Group owns OkCupid and PlentyOfFish. A steep drop can be seen in Match’s price chart as of 1:20 p.m. EST, just as Facebook announced. The decline slowed about 20 minutes later, but the price continued to fall, albeit more slowly.

Facebook dating profiles will be separated from regular Facebook profiles, and dating activities will not be shown to Facebook friends. Potential matches will be recommended based on a number of factors, including mutual friends on the social network. The service is still a while; testing is expected to start “later this year”.

After a few months of testing, Facebook is finally ready to roll out Dating to a large audience. From today, the service will be available for users in the United States, as well as Argentina, Bolivia, Brazil, Canada, Chile, Colombia, Ecuador, Guyana, Laos, in Malaysia, Mexico, Paraguay, Peru, the Philippines, Singapore, Suriname, Thailand, Uruguay and Vietnam. An expansion in Europe will follow, but could take until early next year to occur.

The Facebook Dating opt-in allows users to create new dating profiles, separate from their main Facebook profile. By default, users will not be associated with their existing friend groups, although a “Secret Crush” mode allows you to quietly test the romantic waters without revealing your feelings. Instagram posts can already be added to dating content, and story support will be available soon.