CUNY Academic Commons

r-a-y

User registration spam is prevalent in BuddyPress.
One way to dramatically decrease signup spam is to restrict the email address domains that users can sign up with.
WordPress multisite has a native option called “Limited Email Registrations”. But this option requires you to enter the full email domain. For example, if you only wanted to allow .edu email addresses to register, this is not possible.
This plugin restricts registrations to the email domains that you specify and works in WordPress single-site and multi-site.
Plugin was developed for the <a href="http://commons.gc.cuny.edu" rel="nofollow ugc">CUNY Academic Commons</a>. Licensed under the GPLv2 or later.
<a href="https://github.com/cuny-academic-commons/bp-rsed" rel="nofollow ugc">Follow development on GitHub</a>.
Tested on BuddyPress 2.5, but should work all the way down to BuddyPress 1.6.

BP Restrict Signup by Email Domain

Only allow users with email addresses from certain domains to register in BuddyPress.

rabby

Let the wpmu users select a theme when registering. This plugin should also work with buddypress extended WPMUs. By default the number of themes (screenshots) per line and the number of rows is set to 3. You can simply change it in the .php where it can be found: $n_per_line=3; $n_rows=3; 
Note: This is open source with free incommercial usage. For commercial projects, please contact ahammerl[at]googlemail/dot/com. Steeling open source, is illegal Software Theft. 
Feb 2010: We worry about homehost.com (powered by pointaxis.com) which is using the script without permission and violating the terms.

WPMU Theme Select

Let the wpmu users select a theme when registering

BP Restrict Signup by Email Domain vs WPMU Theme Select