When we talk about judging the importance of a blog, there’s usually a clash of semantics. Some people look at the ‘value’ of a blog (how much a blog is worth), others look at how popular / influential the blog is in its niche and overall in the blogosphere (authority).

If you’re looking to place a dollar value on your blog, read this blog valuation article on Performancing. However, for SEO purposes (or if you want to rank blogs in a blog directory, as we’ve done here at EatonWeb) you’d be better off finding the authority of a blog.

There are many different scales that people use to measure a blog’s importance – Traffic, RSS Subscribers, Search Rankings, etc. Unfortunately for a blog directory, we don’t always have access to this hard data and as a result we have to rely on third-party metrics to do the job.

So which 3rd party metrics can we use? PageRank is widely discredited, and Alexa stats are wildly skewed in favor of tech-related sites. It’s not that hard to fake RSS numbers (although you’d have to be particularly desperate to do so), and Technorati, while being again skewed towards the linkerati as opposed to a more representative sample of web users, also has its share of glitches.

The approach many people have used is to combine a host of metrics and use them to arrive at an aggregated score. For example, SEOMoz’s Page Strength tool factors in linkage data from Yahoo Site Explorer with directory listings in Dmoz and mentions in Wikipedia, amongst other things, in order to arrive at a score out of 10 (like PageRank). This is ‘good enough’ but if you want to compare two blogs with similar scores, it’s a poor measure. Using a larger scale (out of 100) allows you to compare site differences better but the question still remains:

Which metrics are the most important?

  • Unique Visitors / Day – this data is hard to get unless you have direct access to stats (although sites like QuantCast do a good job of calculating this figure).
  • Comments Activity – this is perhaps impossible to measure unless you own the blog yourself, but in terms of measuring reader participation this is an excellent metric to use. If you calculate the comments to post ratio for a blog (number of total comments / number of total posts), it gives you a good indication of how dedicated the audience is.
  • RSS SubscriptionsFeedburner is great in that it allows us to establish an accurate account of RSS subcriptions for a blog. Bloglines data can be hugely misleading (on one of my blogs, Bloglines subs are under 50 and overall RSS subs are over 1000) and there’s no clear ‘multipier’ that you can use either. These numbers can be falsified to some extent, and some niches are not so conducive to RSS reading than others. Still, it’s a good measure for blog importance.
  • Authority Links – There are two ways you can measure authority links quickly. One, you can use Technorati’s stats, which when working are a reliable estimate. Two, you can do a manual search and look at whether certain sites link to this blog or not. The list you would use for such a search would be limited to a few key general sites and after that it would depend on the top sites in that niche.
  • Search Rankings – Blog owners are generally asked to enter 3 or 4 ‘descriptive tags’ during blog submissions. Can we use those tags to determine where that blog ranks for those terms (in Google or across the top 3 search engines), and then use this data to establish the ‘importance’ of this blog?

I hope that this article drives home a few key points. First, it’s almost impossible to build an accurate picture of a blog’s importance using 3rd-party metrics. Two, you can build a ‘working’ picture by using a lot of different stats and using a granular scale to allow for proper comparisons. Third, the more data a blog opens up to the public (traffic stats, rss stats, etc), the easier it is to get a good picture. Fourth, a shortcut to determining the importance of a blog is to categorise the top blogs in a niche first and then use their data to rank new blogs in that niche.

As you go deeper into the mechanics of ranking websites according to importance, it becomes impossible for any two people to agree on how each detail should work. And ultimately that’s the missing link; importance of a blog is as much relative as it’s absolute, and because of this there will always be disagreements over the model used.