Captchas can't prevent bots, just increase their cost.
There's plenty of software out there that can defeat captchas. Not perfectly, but it doesn't need to be. If it's 10% accurate, the bot only needs to try 10 times to get in.
You can also pay people to solve them, there are services for that.
I think it depends on the server version for each instance. 17.4 has a crappy captcha. 1.8.0 has none because it was crap and easy to bot. 1.8.1 isn't out of testing and I haven't interacted with that yet.
Edit that being said, manual sign up approvals and email verification are helpful tools to combat this.
This this the relevant discussion and dialogue surrounding the direction they went to keep it self hosted and open source.
Captchas can't prevent bots, just increase their cost.
There's plenty of software out there that can defeat captchas. Not perfectly, but it doesn't need to be. If it's 10% accurate, the bot only needs to try 10 times to get in.
You can also pay people to solve them, there are services for that.
I think it depends on the server version for each instance. 17.4 has a crappy captcha. 1.8.0 has none because it was crap and easy to bot. 1.8.1 isn't out of testing and I haven't interacted with that yet.
Edit that being said, manual sign up approvals and email verification are helpful tools to combat this.
This this the relevant discussion and dialogue surrounding the direction they went to keep it self hosted and open source.
https://github.com/LemmyNet/lemmy/issues/638
https://github.com/LemmyNet/lemmy/pull/1027