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

cubecolour

A simple and lightweight plugin to indicate external http and https links in posts, pages and custom content by appending a small diagonal arrow icon to the link.
No configuration is required just install and activate.

Indicate External Links

Very reliable has survived many Wp updates and just keeps working.

This plugin just keeps on working

Indicates external links in post, page and custom content.

BP External Activity vs Indicate External Links