There are so many friends who no longer actually talk to each other, but are still up to date on each others' news because they have checked each other's facebook, twitter, myspace, etc. This is not to say that people don't get together over a beer or a cup of coffee, but exciting news is so often broadcasted over these sites, that sometimes the news loses it's excitement... it's appeal.
This could be the intent. Sometimes people just don't want to have to deal with the reactions from so many people. Sometimes people just forget about a friend, but this allows them to reach everyone regardless of who they remember.
I think it it just interesting that people are so keen, and invest so much time in "creeping" or "stalking" others on these websites, but don't take the time to talk to them in person.
Here is a group I created on facebook called:
"I creep peoples' facebook, but don't talk to them in person."