OkCupid is a dating social network.
"We Experiment on Human Beings!"
Following the news of Facebook's social experiments performed on users, OkCupid published a post with the above title, practically boasting about the experiments they have run on people. These experiments included telling bad matches that they were actually good matches and vice versa.
To test this, we took pairs of bad matches (actual 30% match) and told them they were exceptionally good for each other (displaying a 90% match.)† Not surprisingly, the users sent more first messages when we said they were compatible. After all, that’s what the site teaches you to do.
. . .
So we tested things the other way, too: we told people who were actually good for each other, that they were bad, and watched what happened.
On NPR, the president of OkCupid referred to the "charade of consent" with their terms and conditions. 
Reactions to this on the Web:
Requiring first name
On 2017-12-21 OkCupid announced they were removing usernames from user profiles and collecting a "First Name" field that would be displayed on the profile. . This could have privacy implications and be dangerous .
Ahead of the new year, we’re removing OkCupid usernames. It’s starting with a test group and will soon be rolled out to everyone on OkCupid, so all users will need to update their profiles with what they want their dates to call them.
...We’ve also heard from many members of our community that they want to maintain the privacy they enjoy with usernames—with this change, we won’t be collecting full names; instead, we encourage our users to go by the name they’d like their dates to call them on OkCupid.
- 2018-06-24 GDPR dating information update
Going to need some time to digest everything but the OKCupid data dump is full of interesting things.