If beginners to wordpress wonder, "what the heck is a blog used for" .. as in, what are the uses, or Purposes, of a blog -
well, there are a lot of uses, yet I've detailed 9 of the most significant purposes..
http://lifeskillstrainingonline.com/2012/what-is-a-blog-used-for
Beginners to wordpress may wonder, "what is a blog used best for" - 1 thing that springs to mind is Blog Branding, or branding yourself. Also essential is video blogging - you can rank high on google more readily when you employ videos - also, your audience may be MORE receptive to video lessons than lessons in writing at your Wordpress blog. Thus, if you're one of the beginners to wordpress, you want to provide VALUE to your readers - and also link out (via External Links) to authority blogs in your niche.
You should want to DO this (link out), for as you give value to your blog readers they'll develop into a LOYAL following. Also, by linking to other good blogs, you develop your list of contacts; when you do this, blog owners often see your trackback and reward you .
Another good purpose or use for your blog is "blogging training". You can deliver a series of wordpress lessons to instruct the readers of your blog.
Okay, you also have to get your message across. Blog communication is at the TOP of the list too then. It is imperative to engage your audience, and get the point across succinctly, and clearly.