There is almost as much speculation and conjecture surrounding Google’s PageRank as there is surrounding the Loch Ness monster. To reduce the confusion, we’ve compiled the most important facts you need to know about Google’s PageRank.

What is PageRank?

PageRank is at the center of Google’s ranking software or algorithm, which was developed by Google founders Sergey Brin and Larry Page. Basically, PageRank is a kind of voting system in which a link to a web page is counted as a vote for that page. Not only the number of links (or votes) counts, but also the source of the vote. If the link came from a page that itself is important, the link will count more and the important of the link’s source will rub off onto the link’s destination page.

Sites that are deemed to be of high quality according to Google will receive a higher PageRank from Google. When you type certain search query into Google, Google uses PageRank and text-matching technology to return a set of search results that are important and relevant to the search query.

The PageRank Bar in the Google Toolbar

Most people use the PageRank bar in the Google toolbar to get information about a site’s PageRank. The bar represents a PageRank from zero to ten – completely white means zero, completely green means ten. A grey PageRank bar normally means that a page has not yet been indexed and a PageRank has not yet been given to a particular page. A grey bar might also mean that a site has been banned, but this is more educated guessing than proven beyond doubt. Unless you have reason to fear your site has been banned by Google, you needn’t worry about a grey PageRank bar.

Why does PageRank fluctuate?

Lately, there have been numerous reports of webmasters seeing wild fluctuations in the PageRank of their pages. A few theories that have been offered to explain this phenomenon include:

• The fluctuations are an effect of Google’s recent Big Daddy algorithm update, which also included a PageRank update that may or may not have had some glitches.
• Anomalies connected to the way Google allocates PageRank to new pages – you might first see no PageRank at all, then get a fairly high PageRank which will drop to a “normal” level after a while.
• Depending on what Google data center you look at, you might see different PageRanks for the same page.
• The PageRank bar in the Google toolbar itself is also said to not be that reliable in general. The real, inherent PageRank of a page may be different to that displayed in the Google toolbar.
• Some changes might simply reflect the fact that you have gained or lost inbound links.

What does PageRank mean for Search Engine Optimization?

The important thing to remember about PageRank is that a good PageRank alone doesn’t mean much; it is not suitable as a stand-alone KPI for your SEO efforts. Your PageRank is not necessarily correlated to the volume of qualified traffic that your site receives, but that is really what your SEO efforts should focus on.

PageRank does give you a rough idea of the quality and amount of backlinks you have and the importance that Google ascribes to your site. Since link building should be an integral part of your search engine optimization efforts anyway, PageRank can serve as an indication of your progress in this area.

Don’t get too worried about fluctuations in PageRank – this could have a number of reasons, and as long as you are not systematically losing backlinks or actively engaging in black hat SEO techniques, no immediate action should be required.