GreyWolf’s SEO blog (which is very entertaining btw) has a how-to post about pretending you represent your competitor’s blog/website on social news sites and then behalf badly in order to get them banned.
I just posted a response (I don’t work for Netscape, I don’t work for Netscape…. gotta keep telling myself that!) that basically this technique works for smaller sites on machine/community driven sites without oversite (think digg), but that it won’t work very well for sites like Netscape where you have humans checking what’s being banned.
However, this kind of thinking and playing is exactly why these sites need to have a staff of paid contributors cleaning things up. There are 20 other ways to game the system, and computers and the wisdom of the crowds are just not as powerful as humans at fixing/detecting gaming.