How to spot spam bot posts

I noticed that the registration validation image has change to a more complex image. I have also noticed that the bot spam has stopped or to me it has looked like it stopped. Can any mods verify that bot spam has stopped or at least slowed down since the change?

[edit] I posted to soon. A spam bot just posted right after I posted this.

 

Yeah I dont see a bot for a while and then as soon as I post about it this smileyyello bot goes all out and makes 5 posts. :angry:

 

To the mods. May I suggest that you delete the spam bot user account because with a bot like smileyyello google will still spider through to the user profile and find the links in the signature. Allowing this would help the spammer getting their sites ranked higher and I don't think we want that.

 

I have seen something new today. A spam bot has posted a reply to what seemed to be a random topic in a random forum. This bot even posted a some what relevant reply to the topic. It did not post any links but it did have links in the signature. I wont post a link to the topic because I hope the mods take care of it by the time you read this. I also hope the mods remove the account so google will not pick up the new user profile.

I will give you the user name so you can see what this bot is doing. The user name is crespowu and you can do a google search on that name. Google will show you that this bot gets around and does make some what on topic posts but it had the same or similar signature for the profile.

So my question is has the "bot" gotten smarter or has someone done a little more work by hand to make the posts look more real?

I think it might be a good idea to do a search query on the SQL database for any links in a profile signature and try to eliminate any spam bots that got through. This should be pretty easy to do for anyone with SQL experience. Just make a search with these parameters. Find all user accounts with "http://" in the signature where total posts is less than say 10. This should limit the results to possible spam bots and throw out true active users.