PR: the parallels between Page Rank and Public Relations

In SEO circles, the term PR is more likely to refer to Page Rank than Public Relations.  However, in the world of online PR, both have a role to play. In fact, the parallels between Page Rank and Public Relations are closer than you might expect.

But what is Page Rank? Phil Craven’s explanation is the best I’ve seen:

PageRank is a numeric value that represents how important a page is on the web. Google figures that when one page links to another page, it is effectively casting a vote for the other page. The more votes that are cast for a page, the more important the page must be. Also, the importance of the page that is casting the vote determines how important the vote itself is. Google calculates a page’s importance from the votes cast for it. How important each vote is is taken into account when a page’s PageRank is calculated.  PageRank is Google’s way of deciding a page’s importance. It matters because it is one of the factors that determines a page’s ranking in the search results. It isn’t the only factor that Google uses to rank pages, but it is an important one.

Phil also highlights some other key factors about Page Rank that are not immediately obvious:

The values shown in the Google toolbar are not the actual PageRank figures. According to the equation, and to the creators of Google, the billions of pages on the web average out to a PageRank of 1.0 per page. So the total PageRank on the web is equal to the number of pages on the web * 1, which equals a lot of PageRank spread around the web. (Google passed the trillion mark for indexed pages last year and says it is adding billions daily). The Google toolbar range is from 1 to 10. (They sometimes show 0, but that figure isn’t believed to be a PageRank calculation result). What Google does is divide the full range of actual PageRanks on the web into 10 parts – each part is represented by a value as shown in the toolbar. So the toolbar values only show what part of the overall range a page’s PageRank is in, and not the actual PageRank itself. The numbers in the toolbar are just labels. The toolbar value is a good indicator of a page’s PageRank but it only indicates that a page is in a certain range of the overall scale. One PR5 page could be just above the PR5 division and another PR5 page could be just below the PR6 division – almost a whole division (toolbar point) between them.

A page “votes” an amount of PageRank onto each page that it links to. The amount of PageRank that it has to vote with is a little less than its own PageRank value (its own value * 0.85). This value is shared equally between all the pages that it links to.

From this, we could conclude that a link from a page with PR4 and 5 outbound links is worth more than a link from a page with PR8 and 100 outbound links. The PageRank of a page that links to yours is important but the number of links on that page is also important. The more links there are on a page, the less PageRank value your page will receive from it.

If the PageRank value differences between PR1, PR2,…..PR10 were equal then that conclusion would hold up, but many people believe that the values between PR1 and PR10 (the maximum) are set on a logarithmic scale, and there is very good reason for believing it. Nobody outside Google knows for sure one way or the other, but the chances are high that the scale is logarithmic, or similar. If so, it means that it takes a lot more additional PageRank for a page to move up to the next PageRank level that it did to move up from the previous PageRank level. The result is that it reverses the previous conclusion, so that a link from a PR8 page that has lots of outbound links is worth more than a link from a PR4 page that has only a few outbound links.

Outbound links are a drain on a site’s total PageRank. They leak PageRank. To counter the drain, try to ensure that the links are reciprocated. Because of the PageRank of the pages at each end of an external link, and the number of links out from those pages, reciprocal links can gain or lose PageRank. You need to take care when choosing where to exchange links.

So what has this got to do with public relations? Think of it this way. You could consider PR as the attempt to gain positive “votes” from a target audience. And the votes from some places are going to be more important than others. In a media relations context, you can either try to get lots of small circulation coverage (Page Rank 0 links) or a small number of more influential titles (ie a link from a Page Rank  8 page – in media terms the home page of national newspaper. The analogy holds up because not all pages on a site have equal page rank). The further up the influence scale you go, the effort required increases logarithmically. And it’s better to be the only brand mentioned rather than one among many – because the “voting power” of the linking page is spread equally amongst it’s links. However, this only applies if you are comparing titles with similiar influence. Getting talked about in the FT with other companies is better than being the only one being referred to in a less influential title.

Take the example of PR as a keyword term – see full analysis here. The Wikipedia page ranks number one – even though it appears to have comparatively fewer backlinks than other pages on the results page. However, when you examine the Page Rank of those linking pages, you can see that they are from higher ranked pages. Quality trumps quantity.

Also, you need reciprocity. As shown above, to increase your authority, you can’t just make the communication one way – you need “votes” to come back your way.  But they have to be the right kind of links – and how you ask for them will have an impact on whether or not you will get a return link (in public relations terms, this is equivalent to ringing up a journalist and asking him to write about your client with no attempt at relevance and personalisation. Or actually taking the time to research a properly targetted pitch).

I realise – like all analogies – this one breaks down. But in the world of online PR, public relations and Page Rank are not as different as you think.