Bob Wyman recently slipped a mention of the new LinkRank analysis from PubSub into the discussion of top N blog lists, and now the analysis is live. In general, I have liked PubSub's approach to profiling. They solved an interesting problem (how to put all the information on a single page) in a reasonably elegant manner. The latest addition essentially adds an extra column to the table (with two new fields per cell) and an additional graph (again, with two new variables tracked).
As Wyman mentioned in his initial post, the new graph displays the LinkRank and the percentile of the blog. For illustration, here is the graph for this blog as of today:
It took me a while to really grok the graph. Upon reflection, I realised that I was used to seeing percentile information expressed as a shaded region on a graph (as percentile in the contexts I have seen implies the range of instances that are subsumed by the instance under consideration - thus a child in the 80th percentile in height is taller than 80% of all other children of his age). In addition, as in the child example, the number is expressed as the inverse of that used by PubSub. My understanding may be entirely incorrect here, but it is the reason I had some difficulty at first.
Another issue is the range of values. I range from 25, 000th in LinkRank to somewhere around 500. For blogs of a more stable rank at the top of the list, it is hard to make at any fluctuations in the small numbers, this is even more the case for the percentile value. Here is the graph for Battellemedia.com:
The small number issue is interesting as it illustrates the relationship between the metric and the pragmatics of presenting the metric in an intuitive and consumable graphic. It may be that for this metric, a non-linear scale would produce a better presentation.
As is discussed elsewhere, Wyman's metric gives more weight to recent links. This means that regular posting is required to keep a high rank. For me, this highlights an important part of the whole ranking discussion: what is the meaning of the rank? Wyman's rank conflates volume/time and in-links and so, if it is used to judge quality, or authority, it means that more posts more frequently are better than fewer. I'm not sure if this is how I judge the quality of a blog. Blog posts are time stamped, but not all posts contain time-constrained information.
I'm not going to comment on rank algorithms here, but will say that there are many types and uses for blogs. Just as tags might have been a good idea, it is easy to see how they have become noisy and spamable - becoming things in their own right rather than descriptions of object data. If ranking algorithms like this do the same thing then we will artificially value features of blogs which perform well in such rankings.
Anyway, I have to stop here as I need to write another five posts today to keep my rank up...
BTW, the link to 'learn more' on the site is broken.