The Microsoft Community team in corp have released betas of TagSpace, Microsoft Forums and Microsoft Blogs. The ethos is for us to provide plumbing to make it easier for communities to link up and share information.
Browsing to the "Help Build Microsoft Community Applications & Services" page provides details of each area. There's an interesting video demonstration of TagSpace which in essence is comparable to del.ici.ous which enables you to tag your favourite websites and search on another's selections. The FAQs clearly state that our intention is to "provide the plumbing" to integrate services rather than compete with existing solutions.
The Frequently Asked Questions site is pretty good
To try TagSpace et al for yourself simply browse to the beta site and please provide feedback to enable the tools to be built around your needs.
The remit of such tools is to make it as easy as possible for emerging communities to get up and running with the minimum of hassle and expense. Let's see how close the betas get to real World requirements.