I'd say the real value is in understanding that there are fellow hackers out there who you would like to meet, and actually sending them a message saying "Hey, how's it going? I noticed you work at Job A", or "I noticed you're interested in X"...

There's not really much value in friending directly, but if you make the effort to get to know new people, as I will, I think it's a good idea. There's always value in meeting somebody new.