edacsac - 8:00 pm on Mar 1, 2010 (gmt 0)
I've been building similar functionality into some of my web sites and some customer sites for years, long before I've ever tried facebook. Not for the same reasons, but the code is in place and I can steer it anyway I like, including the way facebook does it.
It's not so much some genius idea as it is good relational data management.
If it's really as general as a scrolling news feed, with links to participate in news item and admit certain users or groups access, then it's not going to hold up. Even the most popular CMS's do this and have been for years. Internal business intranets do this to an even greater degree.
The first time I visited facebook I realized this. It took 10 years or better for someone to take the same old code and actually market it in a way that the masses jump on.
Now I have to go read some patent claim to completely understand. If they patented data management 101, then I give up.