When building a website with a CMS, or paying someone else to do it, there are some things to look out for, that may have an impact on your websites search engine optimisation.
Even before pen hits paper (or keys to the keyboard) writing content make sure you investigate your CMS partner/software for these possible issues;
- Speed of rendering, the page has to be delivered to the spider quickly, remember web spiders dont 'see' the images so ignore them (thats a usability issue), but some CMS, build their pages slowly, or the databse they connect to is slow etc etc. I have used this before and found it good to help tune my CMS's in the past http://www.websiteoptimization.com/services/analyze/
- Page Errors, this can really harm your site. Every CMS should display some kind of user message if an error occurs, but what if the error only happens when a spider hits the page? I would advise using google webmaster tools and Yahoo site explorer with your site, at tleast this way you can see any errors that the spiders are showing up.
- Fancy controls/Ajax etc, My CMS uses very little ajax to display content, and there are no fancy javascripted menus/controls anywehere to be seen, its all plain old HTML, rememebr the spiders on read text, so how it looks is irrelevant, the best looking site can get 0 search results. Ajax and javascript can is used incorrectly actually hide your content (if used well it can help your content too) from the spiders
- HTML structure, this is the biggest problem with any web page (not just CMS based ones), the page must follow the basic HTML structure. So Meta tags, CSS and javascript in the HEAD area (except google analytics move them to the bottom of the page), content in the BODY area, Header tags in the correct order on the page, H1 at the top, then H2 etc etc, use P tags for each section of relevant content, use UL/LI for lists, etc etc.
A spider will index the structured content faster if its in the right place.
Lots of info, I am sure some will disagree, however these are all things I have had to look into over the last 2 years of developing OCRE and the best bit is every site that uses it has been indexed by google pretty quickly and all have relatively good search results.
If you can get some demo time with the CMS before you buy it, take the oppurtunity to see if you can break it.....No CMS is 100% perfect, OCRE isn't and well I dont think there is such a thing. Ask if the CMS can be added to, is it an opensource platform, who developed it, what the support is like etc etc.
A CMS will give you all the power you need to control your website, remember to check it does everything you need it to before you shell out your hard earned cash.