Re: COMING IN FROM NING
1) This is indeed something that only comes with WPMU.. But WordPress 3.0 is almost ready and multi-networks (read=user blogs) are a option in 3.0.. So you might enable this feature for your community as soon as WP 3.0 is released.
2) You can add youtube videos into the activity stream by using the oEmbed Plugin created by Ray. https://wordpress.org/extend/plugins/oembed-for-buddypress/. Simply copy and paste the URL to the video into an Status Update, Reply or Blog Comment, and it’s gets embedded into the stream. Awesome!
3) Currently you have two options for this:
keep an eye on this topic: https://buddypress.org/forums/topic/bp-album-new-features-requests-and-discussion. It’s an album plugin which is shaping up nicely and offers albums for your users.
or check out http://www.buddydev.com which offers BP-Gallery. A media plugin which allows the creation of video, pictures and audio galleries. It’s currently almost in it’s final stages, but if you would like to use it you need to have a paid subscription.
I hope you enjoy BuddyPress 
