Is including a blog in your site worthwhile?

[V-Network.com]

I've been reading in a bunch of places as to whether or not blogs are worth the trouble & whether or not the really get more traffic to your site. Granted this might be newbie territory, but I have a hard time believing anyone really wants to read or get that involved in opinion pieces since there are so many sites out there that are filled with people sharing "stuff"...

So...

In order to get the most out of the time you put into these things, what should they be about? Is it strictly PR? Industry related news? Site promotions & deals you're running?

Appreciate the input...