Is this Blog site endorsed by the TYPO3 Association?

Yes. This is an official TYPO3 site from the project.

Can I have a blog here?

The site is aimed at the TYPO3 community so if you're already visible in the newsgroups or active in a way or another in the community then we will be glad to open a blog page for you. Blogging is supposed to be an activity you maintain. So we kinda suggest you at least do a blogpost every two months. Blogs that do not show any activity for more than three months and where author does not respond will be removed and archived.

Which tools do you suggest to help bloggers?

We suggest that you read the introduction page where we suggest a few tips and tricks.

Is TYPO3 the only topic available here?

You can blog about everything which moves you, but at least about half the blog posts should be about TYPO3.

Who should I contact in case of complaints?

Please write an email to participate(at)typo3.org.