Listing in one relevant category. Reciprocal link is encouraged, but not required. The amount you bid determines where your site ranks in the search results. The higher you bid the higher your site appears in the results. This marketing concept is called branding and is most widely used in television advertising.
Successful companies advertise repeatedly to establish their brand.
Build Credibility - when users see that you pay to advertise your site, your credibility with them increases. Internet users are very skeptical, especially toward wedding sites. They are more likely to visit your site if you pay to advertise. The thought process is simple - they pay to advertise their site, they must be for real.