CMS are great for websites and for SEO but picking the wrong one can turn your ecommerce dreams into a nightmare. There are many web companies out there charging the earth for CMS they claim to have made themselves and is the best and so on. But very few are SEO friendly, and furthermore the best ones are free anyway and take no time at all to install.
Here are some guidelines that a CMS must adhere too, to be classed as SEO friendly.
You need the ability to add/edit a unique title and meta description to each page. Also helpful but not essential is the ability to add additional meta tags. What is bad in SEO is if each page is titled with your business name.
You need static customisable URLS. No dynamics if possible.
You need the ability to add your own Alt Tags (alternative text) to an image and add an appropriate description of the image.
You want to be able to add and edit page headers (H1, H2 tags). Each page should have a unique H1 tag. You want to be able to edit the header without it changing another field e.g. title.
You need to be able to add bold/italics, bulleted lists, just all the basic word processing functions. You also want to be able to add hyperlinks to link to other pages. Flexibility is key.
You should be able to easily update your site navigation so you can ensure all pages are crawlable.
The ability to redirect pages is beneficial.
The ability to show your content via rss.
You need the ability to create and update sitemaps. Ideally one for the site to help people navigate , but also an XML one to help with indexing.