If you're running an online business then Page Rank is important but you won't get it automatically. You need to post quality content, generate some traffic and build up some links; in that order.
Some say page rank isn't as important as it used to be but all the top pages in Google have a high page rank. The ways to achieve that are a little different now since Google recently changed their indexing algorithm. Because of this the advice about building backlinks isn't wholly accurate.
I'm not saying backlinks aren't important they are but they're not the main focus for Google's indexing algorithm anymore.
Hubpages is a great place to post content as it's automatically a very interactive site and that's what Google is most interested in now.
I'm in the middle of putting together a system to generate web site traffic and that will automatically improve search engine ranking and therefore page rank (they're not quite the same thing). You can read more on my Hubs.