Changing CMS, are there SEO effects?

[PlusPort]

We want to change our cms from typo3  to CMS made Simple. We have done this already for another site and it effected the rankings. Have you got experience with this? What factors are important for SEO to consider? Is it normal when you change from cms the rankings will drop?

[xrobbanx]

Actaually TYPO3 is very simple if you set it up correctly. Aslo there are some really good SEO modules for TYPO3 like http://typo3.org/extensions/repository/view/tq_seo/current/

[Marcus_Miller]

Changing the CMS itself will not cause a drop, but any actual changes to the content or structure of the pages may cause changes (good or bad).

As with Craig, I am no big fan of CMS Made Simple, have you thought about maybe migrating to one of the other open CMS platforms? Hard to advise without knowing your site and goals but WordPress can take some beating for most small business websites and Joomla! & Drupal provide options if you need more flexibility.

[CraigAddyman]

Yea I agree if everything is kept the same you shouldn't see much difference but you should expect a drop and prepare for this.

That said you need to ensure the new CMS is capable of accommodation the  changes, again be well prepared.

If you intent to make changes then ensure you follow all the necessary steps and procedures that come with a site migration.

As it effected the ranking last time you can be sure it will happen again, you might want to ask yourself why your wanting to change content management systems and weight up the pros and cons, I have a site on CMSMS and I personally don't like it but each to their own

[mosaicpro]

I think that if you keep the same [seo structure - url, title, h1, content, etc] you should not drop in rankings at all

Check this :

http://www.google.com/support/forum/p/Webmasters/thread?tid=3d2a9df109e09763&hl=en

Conclusion is mirror your site especially with URLS so nobody will know you have a different cms -> you don't loose anything