Naming probably mattered more in the era of phone books and neon signs: if you didn't recognize the name as relating to the service you wanted, it counted against the name.
These limitations aren't present with a URL; a short meaningless name is probably better than a long meaningful one.
An interesting recent phenomena is companies replacing their trusted names built up over many decades with a short, catchy, meaningless one: the rebranding of Washington Mutual to WaMu comes to mind.
A better article on the same topic from the Post: http://www.washingtonpost.com/wp-dyn/content/article/2007/11...