Most people posting here probably know that there are a lot of trading bots out there, but does it work? How could you tell if one is working?

Most of them probably have promises that you could gain profit, but that's different. People should understand that bots are told what to do and would react to what they have set in the parameters. It still depends on how the market would go and how the strategy you would have set would respond.

What do you think about trading bots in general?

[Shameless plug] Everybody who has checked out my profile knows I'm affiliated with Gunbot but check it out.
Are you interested in trying it a bot out for free? Check it out on my site https://gunbot.ph and check the Gunbot Trial. You could try it for three days for free.