I have an account at Dutch social network Hyves.
It has about 2 mio active members which means a lot of my friends have an account as well. I’m not really into the network because of time constraints. So besides replying to the occasional message from friends and updating my status (‘WieWatWaar’) I don’t spend a lot of time in their place. Just recently they implemented a new set of features like adding a number of widgets – no Flickr, huh?! & last.fm doesn’t work… – and the possibility to import your external blog on your profile page. So I decided to add the feed of this blog. A few days ago I received an email message from Hyves that one of my friends commented at one of my posts. I checked it out and just realized at that moment that the comment was only to be seen in Hyves and not in the comments section here at WordPress. That sucks because I really want to aggregate all my discussions over here. The effects of a walled garden in action. Thanks very much. I deleted the feed of my blog at Hyves.
BTW I tried to add a link to my blog in my Hyves profile for the interested friend and it says it saved it but it doesn’t show up in my profile. Nice usability. I gave up after three tries.
UPDATE: bonus link from the Social Silo Liberation Front 😉