DeannaS

kgraeme

When users are first created, they are automatically assigned to the primary blog. But, you may want to set them up on multiple blogs by default. This is especially helpful if you’re using bbpress or other forum software where the user needs a role on that blog in order to participate. This plugin allows site admins to set the default role on as many blogs as desired for all new users.

WPMU Default User Role

Lets site admins define which blogs a user should automatically become a member of, and with what role. Multiple blogs supported.

isikom

Category Text add a widget that allow to add arbitrary text or HTML code, different for each category of your blog. 
It’s very usefull for SEO, because you can make different text for different category, so also different banner etc. 
Now you can select also the home page position.
The plugin born from idea of <a href="http://www.rossozingone.it" title="web agency" rel="nofollow ugc">Vanny Rosso</a> for his blog <a href="http://www.fantagiochi.it" title="on line games" rel="nofollow ugc">Fantagiochi</a>

Category Text

category text allows you easily to add a widget for a Category Text-Box.

WPMU Default User Role vs Category Text