How should I deal with SEO-unfriendly links?

Question

I'm working with an e-commerce site that is heavily data-driven and dynamically generated, so many of the links are generated dynamically as well. The problem is that the system we use is not open source, so whatever links are generated by the system can't be changed. I'm using ISAPI Rewrite to rewrite requests from friendly URLs to the ugly ones. Should I 301 redirect from these ugly unchangeable links to the friendly ones? So then I'd have two scenarios:

nonfriendly url request -> redirect to friendly url
friendly url request -> rewrite -> load content from the nonfriendly url

My SEO experience spans about a week, so I appreciate any guru input. :)

Answer 1

The Microsoft URL Rewrite Module for IIS 7.0 provides flexible rules-based rewrite engine that can be used to perform broad spectrum of URL manipulation tasks, including, but not limited to:

• Enabling user friendly and search engine friendly URL with dynamic web applications;
• Rewriting URL’s based on HTTP headers and server variables;
• Web site content handling;
• Controlling access to web site content based on URL segments or request metadata.

Answer 2

Yes, 301 from the old links to the new ones. That will preserve any linkjuice the old ones had coming in.

Answer 3

It really depends.

Lets say the link is shop.com/?item=cake. Redirecting this to shop.com/cake will not do you much good because you had to get there the same way in the first place.

Something like that is good it the links are absolute on the page, but if the user begins with simply an input where they search or some tags probably not the best solution.