We are pack animals, it is why dogs evolved in to our family. Isolation is a severance from our natural social state and is hurtful. I think one of the great benefits of the internet is that it is possible to meet and befriend people outside of the normal social routes. It is not a cure for isolation, but friends you game with or chat with or share stupid stories with is a help.
The problem is that reddit and digg killed the conventional forum, so no one really cares who you are any more (unlike when people would start to 'know' regular posters on forums). Now it's a crapshoot of random people and a smattering of comment replies if people vote on your comment. No personality, no real interaction.