The difference now is that people who are in the acquaintance-Internet friend spectrum can still be reached easily with an email, a tweet, an instant message… if you wanted to. So they always feel kind of "there" even if you don't actually communicate with them. Until, like the author, you try to reach out and they don't reply back.
It's kind of an interesting thing of online "friends": you can be in touch with somebody in a chat room or a forum for years and feel like you know them well (at least in the context, you've known them), but they can just disappear one day and you won't know if it's because they died or just moved on to other things.
I was thinking about that about a guy I've been playing Words with Friends for probably three years. I only play with him because I know we're about the same level and it's hard to find players like that. (we were matched randomly) But I don't know anything about him except for his first name, most likely his birth year (based on his username) and possibly the fact that he lives on the East Coast based on the time he plays his turns. If he were to stop playing, I wouldn't be able to tell the difference from him being dead. It's a strange thing.