It's not the CMS, it's what you do with your Website. The content, the backlinks, the template etc. Joomla has a big community as well as good SEO plugins
I know its not the cms alone but I was thinking there must be more friendly cms's than others. I use typo 3 for example which I am not over the moon with
Look for SEO plugings in typo3 or try another CMS. As mentioned before. Joomla has one of the biggest communities out there.
I don't think so. The most important SEO work is done off page, like backlinks, so it doesn't matter what you use. And a CMS does more work in the background - Admin Panel etc. As long as your front end uses a good template and you have good content it should be fine. And that can be accomplished with almost any CMS.
A CMS based system is some thing good because you have to put something interesting or attractive on the website without wait for the ftp uploading/downloading........