Holy microcrap Batman!

Brand loyalty is the phrase you're looking for.

Microsoft needed blogging, because everyone was blogging. People who ran companies that make
beans were blogging. Grandparents were blogging. So Microsoft needed to be blogging too. Some
individual Microsoft employees had been blogging, as ordinary users of (often Linux or *BSD
based) blog sites. But at a corporate level Microsoft couldn't just use an existing blogging
site, and they definitely couldn't install some sort of LAMP solution. It needed to use as
many Microsoft technologies as possible - So they went with Community Server.

But Community server isn't very good. It's riddled with bugs, and it seems that adding
features you might want is either very difficult, or at least hard to do without effectively
forking the project. Microsoft's own Community Server installs have had weird problems,
outages, big feature gaps compared to competing blogs people are familiar with and so on.

So it all looks rather poor, particularly for the Microsoft bloggers working on .NET (the
platform used) and to a lesser extent SQL Server (the RDBMS used). It's also causes
embarassment for the IE group (it doesn't obey anything resembling web standards, so they get
beaten up about that, and it sometimes used to trigger rendering bugs in IE, so they'd get
beaten up even more about that).