Boone Gorges

CUNY Academic Commons

Allows admins to import data from an arbitrary RSS feed into their BuddyPress sitewide activity stream
The plugin imports RSS feeds every hour. You may find that you need to decrease your Simplepie cache time to make it work: 
 add_filter( ‘wp_feed_cache_transient_lifetime’, create_function(‘$a’, ‘return 600;’) ); 
reduces the RSS cache to ten minutes, for example. Put that in your bp-custom.php file if you are having problems with the plugin.
At the moment, the plugin uses the Author field from the RSS feed to look for a matching author in your WP database. If it doesn’t find one, it uses the unlinked text ‘A user’, as in ‘A user edited the wiki page…’.

BP External Activity

Allows admins to import data from an arbitrary RSS feed into their BuddyPress sitewide activity stream

Tran Ngoc Tuan Anh

This plugin adds rel=”nofollow” to all external links in post content. So, your flow of PageRank can not run to other websites and your blog’s SEO is improved.
The internal links are unchanged.
Requires PHP5.

BP External Activity vs External Nofollow