I had someone copy an entire post of mine word for word and only change the pic. Wasn't detected by any bot. I found it because I happened to be browsing the new page and it popped up.

Another thing I have noticed is several times after I make a thread about something another person will make a tread on the exact same subject but rewrite it to look more appealing to people. I'm not a writer so it's easy for someone who is to do. At least 2 of those posts submitted not even an hour after mine made hundreds while I got pennies.