There’s now a free SEO (Search Engine Optimization) Toolkit that easy to install (via the Web Platform Installer or directly) and use with IIS to analyze your website. It offers reports to help you make your site more search engine friendly, helping to increasing traffic (and helping to get the right kind of traffic). The reports can also identify problems (e.g. missing content, incorrect links, etc.) that can sometimes be difficult to find.
There’s also a 14 minute video walkthrough of how to work with the SEO Toolkit and what it can do for you.
By the way, the SEO Toolkit is just one of many IIS Extensions available (logging, routing, dynamic IP restrictions, smooth streaming, and more.)