You can request a friendship by clicking on the name of a person on their post, then adding them to your contacts. You will be prompted to send a friend request.
You can go in the chat room or one of the off topic threads in the lounge and make friends like that, if that's how you mean.
"What, exactly, is the internet? Basically it is a global network exchanging digitized data in such a way that any computer, anywhere, that is equipped with a device called a 'modem', can make a noise like a duck choking on a kazoo." - Dave Barry