The Page Rank system is a powerful system of Google that shows how well known a website is in the world. In fact it has a lot to do with the number of links to your website and the number of link inside your website.
This means that when you have a lot of attractive content on your site webmasters will make links to you saying: Hey look at that site!
So good sites are more populair and get a higher ranking.
A good web site designer knows that and he knows how to create an attractive website. If you don't know how to make much a website just read the articles in my Weblog or search the internet for this information. A lot of articles are writen on this subject. It is important for web designers to do that.
When visitors search for a webprofessional on WebmastersLookup.com they can use the Page Rank bars as a good indicator of the skills of a webprofessional. Together with the presented roles, experience and location you get the whole picture. I agree this is not very nice for the fresh websites which has a PR of 0 and for the beginning designers who still have to learn. On the other hand, good web professionals are more expencieve. There is work for every one and a high PR doesn't come overnight...