Craigslist has dropped personal advertisements after Congress passed a law making websites liable for promoting sex trafficking and prostitution.
The Fight Online Sex Trafficking Act (FOSTA) drops legal protection for websites that "unlawfully promote and facilitate prostitution and websites that facilitate traffickers in advertising the sale of unlawful sex acts with sex trafficking victims".
It also makes website liable for content their users post.
In order to stay above the law, Craigslist has taken the decision to close its personal ads service – ensuring the tool cannot be misused.
A statement from Craigslist said: "We can't take such risk without jeopardising all our other services, so we are regretfully taking Craigslist personals offline. Hopefully we can bring them back some day.
"To the millions of spouses, partners, and couples who met through Craigslist, we wish you every happiness!"
It was initially thought the missed connections section, which reunites people who met briefly or shared glances, was to be removed too, but Craigslist appears to still be running them.
Reddit has also banned its sex worker sub-reddits, such as its escort pages.
A statement on the website's policy announcement page read: "As of today, users may not use Reddit to solicit or facilitate any transaction or gift involving certain goods and services, including paid services involving physical sexual contact."
The decision has been met with anger from many people, including sex workers.
Amber Ashton tweeted: "This is going to hurt the most marginalised struggling workers the hardest and I’m in actual tears about it.
More from Science & Tech
"Time to stratigise how we can help those who will need it most."
Another Twitter user posted: "If you think this isn't a move towards shutting down, not only sex workers, but 'sexual deviant relationships' of all kinds (queer, interracial, casual sex, non-monogamous, etc) then you are naive, my friend."