When I pay Yahoo! (etc.), does that guarantee me good positioning?

Unfortunately not. When you pay Yahoo! all they guarantee is that they will consider your site for inclusion. Many people pay their $299 fee only to find their site declined! Submit Planet has a lot of experience in submitting to Yahoo! and getting sites indexed. So far, no site we have submitted has been declined. When we submit client sites to Yahoo! we use our experience to help get higher positions in the directory. The only time you can guarantee positions when paying is by bidding on your keywords with Overture (or similar). This can work out to be very expensive.