Search Engines and Content Management Systems
I have seen a lot of discussion over the years regarding search engines having trouble indexing sites that use content management systems. The biggest problem sites run into is using query information for the CMS to determine what content to show. This is when all of the pages look like index.php?articleId=X.
We are working with a client that has a similar problem. He has well over 100 pages on his site, but Google only recognizes about 10. Each of his pages is generated off of an ID parameter, so after the first 10 hits on what Google thinks is the same page, no more pages are indexed. It probably doesn't help that a previous consulting firm informed him that an XML sitemap was unnecessary (though I'm not sure it would really help).
While we remain platform agnostic at HPG, we have had good luck with the Joomla CMS. Joomla has been around quite awhile (starting as Mambo) and has quite a following. It also contains out of the box search engine friendly URLs. We use Joomla for the HPG site and are steadily climbing our way up the Google organic rankings. It occurred to me though after reading a search blog with some "unofficial" ranking tests (I'll find the link and update this entry with it) that, especially with Google, it may be more important to have deep links to the content than fully spiderable content. This is because the ranking test found that a page with basically no content but tons of inbound links could outperform just about everything else for the chosen keyword. In our "unofficial" testing, we have consistently found that Google results are considerably different than Yahoo or Microsoft (I'll leave out the Bing vs. Live debate), and both Yahoo and Microsoft respond better to onsite optimization where Google responds better to offsite optimization.
So where does this leave us on the CMS and search engine front? Well, since Google responds better to offsite optimization/link strategy, and has 80% or so of the global search volume, it would seem the CMS choice/search engine friendliness has little bearing on overall ranking. Still, it makes sense to at least have spiderable URLs so all of your pages are indexed. Beyond that, it probably doesn't matter much as long as you or your SEO agency are working on a strong link program and continuing to develop optimized copy.
So next time someone says they don't want to use a content management system because it will hurt search engine rankings, call their bluff and see if they can give a real reason why. Find out if they have a plan to work around any perceived limitations. If they can't answer either to your satisfaction we'll be happy to help you out (sorry, had to throw a plug in there!)