Recently I fielded a question about making dynamic URLs more search engine friendly. A specific site example was not given, so my response was not as detailed as I would have liked, but I thought a post of some recommendations here might be helpful. Feel free to comment on anything else that should be considered to make dynamic urls easier to crawl.

Simple is best for crawlable URLs, although Google and Yahoo! are much better at crawling complicated URLs now than they were a year ago. As a general rule, avoid including session ID information in the URL and if you do need to include parameters, limit it to two and limit the number of characters per parameter to ten or less. Your solution might involve some of the following:

• Server side URL rewrite (specifics depend on platform and Web application) or 301 redirects to crawlable URLs from dynamic.

• Creation of an XML or plain text site map for submission to Google Sitemaps and Yahoo!. With Yahoo!, the text file would contain a list of URLs with each URL at the start of a new line. There are many third party Sitemap programs listed at Google.
• Creation of an HTML sitemap with 100 text links or less. If you have more than 100, break the sitemap into more than one HTML page.
• Get inbound links deep into your site from other relevant sites, blogs, directories, etc. - not reciprocal, and don’t worry about silly things like page rank.

Google Webmaster Guidelines offer some good advice as well.

[tags]search engine optimization,seo,link building,dynamic url optimization,mod rewrite,301 redirect,google sitemaps,yahoo sitemaps,sitemap[/tags]