Plugins for vBulletin:

• Advanced guest posting & registration – allow guest to post a new thread or reply and then register to save their reply
• “See More” Google Custom Search – help users find more useful content & earn more with Google Adsense in the process! 
• Advanced Noindex, Move & Prune – Advanced Noindex, Move & Prune makes it amazingly easy to clean up your forum and only display your best content to search engines.
• Amazon Associates Links – Automatically rewrite links (on the fly) to Amazon.com/.ca/.co.uk/.de with your ID.
• eBay Partner Network Links – Automatically rewrite links (on the fly) to eBay that contain your EPN ID’s.