I was a member of a particular forum where there was a user who used to post useful guides on various topics. He got a lot of likes and appreciation from users and the staff alike. After a month or so, another member pointed out that those articles were stolen from other sources.
The staff were furious. If there is one thing that could put a webmaster in trouble is copy-paste content. Google can easily detect stolen content and will punish you for that. There are also legal complications too.
Do you stand guard to such problems ? How do you monitor the content posted on your website by unknown people.