It's quite interesting how powerful the internet is when it comes to creating a sense of false intimacy, compared to other media. I have a number of people whose blogs I read, but who don't read mine, because they're not my friends, they don't even know I exist. But yet, I feel like I know them, it feels like there's a relationship, when there isn't. I think blogs make it worse (or more effective), because of the imagined reciprocity. You don't converse on a blog, you read other people's entries, and you write your own and that's how you communicate. So you subconciously imagine that everyone on your friendslist knows everything you've posted in your blog, just like you know everything they posted in theirs. Facebook works the same - and basically any other site with a friending function.
There's enormous economic potential in it, if managed right. I bought Nurk because it was written by my "friend" Ursula Vernon. It's an amusing book, but I wouldn't have bought it if I didn't read her LJ. If I happened on a copy of Batman with a Dustin Nguyen cover, I'd be inclined to buy it, because I watch him on deviantArt
Interestingly, it works with TV actors too - more so, for me anyway, than movie stars. I watch Castle because I miss Firefly, and it has Mal in it. I checked out How I Met Your Mother because of Willow, and The Sarah Connor Chronicles because of River. I watch Dollhouse because I expect Joss Whedon to entertain me, but Castle to support my "friend" (helps that it's also entertaining).
Now, I recognize that this is happening, so I can work against it, but I haven't managed to stop it. Should you ever happen to meet any of these "friends" though, you quickly realise they're actually strangers - which can be both sad and good for you.