: Blogging platform that supports group , private , public blogs and advanced tagging Possible Duplicate: Which Content Management System (CMS) should I use? After some bad questions

Possible Duplicate:
Which Content Management System (CMS) should I use?

After some bad questions here, i finally have my main question in mind :)

I need to design a platform that provides:

-Personal blogging (blogs that are view able only by them)
-Group blogging (blogs that only people part of a small group (3-4 people) can see the posts and comment)
-Public blogs

Also about the content itself, i would need

-Advanced tagging (common tags amongst all blogs AND tags specific to a blog in addition to the common)
-Search capability
-Rich text content with photos media e.tc. on the blog entry
-A database that i could access and create custom applications (most read-only) on the data. Also an API would be helpfull.

an example of a custom application would be to select your blog posts and create an offline file (.zip html e.t.c) and have it stored locally on your machine.

After some research:

-Forum platforms are NOT suitable for this as i would have to create hundreds of sub forums with selective security for each of them. It would make administration almost if not impossible.

-Joomla and joomla-alike cms also give me bad signs as i couldn't have specialized tags per category of articles and i suspect heavy coding in order to do it. Also i don't know if it could satisfy my other above-mentioned needs.

-I have found a combo that may work. Invision Board and IP.Blog. IP.blog supports almost all of the features that i want ,but it seems maybe too good to be true (any input of someone that already uses it would be helpful).

Many solutions follow the logic that a blog is public and allow for some level of security on them, which is not suitable for what i want.