This is a intercept from a artcile how this guy got his site banned:

decided to do some SEO for my site (Link in my profile). I was aiming at msn, because I couldn't even rank #1 for my company name on google or Yahoo! even thought I have 700+ incoming links. My company is creating games, so I choosed the keyword "Play games"

I added it once to the title, added it as plain text on the site (Not hidden), I also added a link at the bottom of the site, which I added for SEO purposes only, But It wasn't hidden, so I didn't see a problem with it. I also added the keyword to an image alt tag.

I admit I repeated the keyword 3 times in the meta keyword tags, but all the articles I've read say there's nothing wrong with that, aslong as the same word isn't repeated more than 5 times, which it isn't. I didn't add it after each other either, I used other keywords to seperate them. My description tag is: "Come and play our free games at Crobasoft.com"

I also noticed it took a while for msn to index the changes I did, so I manually submitted my site to msn, once.

Now, my site is removed from MSN, however it's only the index page - none of the subpages have been removed.