Google has added a social networking aspect to Google Reader. Inviting a user to chat (i.e., adding them to your GTalk buddy list and you to theirs) allows you to view their shared feeds in a new section, cleverly titled, "Friends' shared items".
You can add me by adding martingordon at gmail.com to your GTalk buddy list. As an aside, there should be an easy way to link to this action instead of having to provide instructions. For now, I'll call it "Google Readerbook me", in honor of that other social network.
I only have one friend at the moment, Scoble, and there is a major flaw (which I mentioned to him last night and he blogged about): If they share an item from a feed you're subscribed to, you see it twice. For people with many friends and lots of overlapping shared items, the number of dupes that have to be processed can grow considerably.
The solution, of course, is to remove the duplicate items. But let's take it one step further. Show me how many times the item would have shown up in my feed list. I can list six metrics that are no-brainers: friends sharing/starring/subscribed to this item and all users sharing/starring/subscribed to this item. Google Reader instantly becomes a del.icio.us/Digg competitor if they decide to show the "all users" metrics. Perhaps it even turns into a del.icio.us/Digg killer since starring/sharing is such an "organic" action. Since I'm doing it anyway, there's no inertia keeping me from participating and there's no need for me to install and use browser extensions or Bookmarklets to bookmark/submit anything.
It's clear now Google's approach to building a social network is the exact opposite of Facebook's. Facebook first built the network and then tacked on applications; Google first built the applications and then integrated the social network into them. In Facebook's case, yes the network itself has its uses, but I have yet to find a truly killer app among the thousands of Facebook apps ("Zombies" and "Super Wall" aren't going to change the way I live, work, or for that matter, socialize). Google's way is sneakier (in a good way) and this means it may take longer to build up the network, but I feel in the end it'll lead to a more useful social network - the one that enhances the applications I already use.