or...go to the site you want to reference, copy address from address bar, paste to post, done, :-). if the address you want is in your favorites, right click, go to properties, copy address, paste to post, done!
this is great for people like me, who can't remember anything and don't want to type. hyperlinks, in my opinion, are only really fun when you want to label the address and make your label a clickable link.