I run a phpbb forum. I got the idea of just making a category that had only bot access so nobody else could see it, and then posing A lot of keywords in it. would this work?
Pretty sure this is an old "blackhat" technique called keyword stuffing.. http://en.wikipedia.org/wiki/Keyword_stuffing If it was my site/forum..I wouldn't do it! Of course, I don't try to get my sites banned or non-indexed!
Yes you can get banned... I've seen them de-index a bunch of sites for keyword stuffing. Google is pretty smart at detecting them. You will probably get a way with it for a little while, but once Google catches ya it's gonna be all over for that domain cuz you'll probably lose all the traffic from search engines.
the best type of seo is just writing quality content. Don't waste time on keyword stuffing, just write. Google will find you