If you haven’t tried it out yet, blekko.com is a unique search engine. Along with allowing you to customize your own search results (or view results customized by one of its editors) it transparently provides a plethora of data showing why it ranks sites in the search results. The best part is, even if you aren’t trying to increase visits from blekko, their SEO data is very useful.

Getting blekko’s SEO data

It’s simple to get the SEO data from blekko. First you need a blekko account. Then all you have to do is type a URL into the search box, hit the spacebar, and add /seo (what they call a “slashtag”) at the end of your search string.

One of blekko's most distinctive pieces of data is “Host Rank”. This is not so much a ranking of websites but a measure of website authority- like Domain Authority or PageRank. Unlike these other metrics, Host Rank is on a linear scale rather than an exponential scale. Typically a linear scale is a little easier to wrap your brain around. For example, while you might be tempted to think that a website with a PageRank of 4 is only a little bit better than a PR 3 website, we need to remember that this is an exponential scale and the former has a significantly higher authority than the later. In other words the difference between a Host Rank 30 and 40 website is simply 10 points but the difference between websites with Domain Authority 30 and 40 is not 10 points, it is 10 to the power of X points (it is an exponential scale- what's the exponent? ask Mr. Fishkin). Host Rank also avoids a maximum value on its scale unlike the coveted PR 10 website (or comparatively strong DA 100 website).

There's much more to blekko besides another number to compare websites. The /seo slashtag also provides a nifty pie chart outlining what countries the links tend to come from. Although there is nothing wrong with a link from India, for example, if a website is based in the United States and the audience is primarily in the United States, the origin of the links can be indicative of some (shall we say) risky SEO techniques.

I also find the “co-hosted with” list at the bottom of the /seo page very interesting. Does this website have dedicated hosting? If not, that’s not necessarily bad thing but if it is co-hosted with some (shall we call them) questionable websites, that might be a neighborhood you wouldn’t want to be associated with.

Blekko’s data gets even more specific. You can also slashtag a URL with /domainlinks to find a list of inbound links (you can also access this from the right sidebar of the /seo page). Now this list of links most closely resembles the defunct Yahoo! SiteExplorer in that it provides a very long list of links that you have to manually filter through to be useful, but it does a good job giving you an indication of the source of this website’s link authority.

I also like to take a look through a websites /sitepages. This gives a list of all the pages on a website, as sorted by Host Rank. This is a great way of seeing how Host Rank (and presumably PageRank or even Domain Authority) flows throughout a website. Of course, the homepage of any website will always have the most authority- but does any authority flow to interior pages on the website?

Let’s get a little more concrete with this data. We can use blekko’s SEO data to evaluate a couple of web directories to see if we should submit our site to them. Starting with SEOmoz’s directory list, let’s take a couple of authoritative directories (as measured by Domain Authority) and a couple of low authority directories.

The Yahoo! Directory (Domain Authority 100): http://blekko.com/ws/dir.yahoo.com+/seo

Anyone with (shall we say) the means to afford $299 a year has probably submitted their website to the Yahoo! Directory. For a while Google’s Webmaster Guidelines even suggested it. Is it worth the cost? What will we get out of this listing? Let’s use blekko’s SEO data and find out.

/seo

• With a Host Rank of 2,054.9 we clearly see this is a very authoritative website (at least in blekko’s mind). Although this number doesn’t mean much in itself, I bet it’s higher than your personal website.
• Most of the links are from the United States (64%). Not to be so Amero-centric here but there’s nothing in the geographical distribution of the links that would make me concerned here. This is an international directory, after all.
• The site is co-hosted with (wait for it) Yahoo!. Even though it’s been a while since I’ve used Yahoo!, that’s a neighborhood I wouldn’t mind being associated with.

/domainlinks

• Websites actually link to the Yahoo! Directory (who knew) and these seem to be authoritative and clean. It seems like a legitimate and natural backlink profile to me.

/sitepages

• Authority seems to flow very quickly into the directory listings and the Host Rank doesn’t seem to drop-off very fast. If your website falls into one of these top ranked categories you’d definitely want to be listed there.
• One of the top-ten pages, according to blekko, is the list of newly submitted websites. FTW!

The Better Business Bureau (Domain Authority 99): http://blekko.com/ws/bbb.org+/seo

Got a brick-and-mortar along with your website? Why not submit it to BBB.org?

/seo

• This site, according to blekko, actually has more authority than the Yahoo! Directory. It has a Host Rank of 2,948.4. This is tempting!
• It makes sense that 86% of the links come from the United States- this is for US-based businesses, that’s how it should be.
• WOW! What a list of sites are co-hosted with the BBB! Well, it’s co-hosted with pearljam.com so it’s gotta be a good neighborhood! (By the way, did you see Pearl Jam 20? Highly recommended)

/domainlinks

• Sites linking to the BBB seem to be very similar to the Yahoo! Directory and they are all from legitimate and authoritative websites. You wish you could have a backlink profile like this site!

/sitepages

• Unfortunately the first business I found was on the 6^th page of blekko’s /sitepages results. Most of the authoritative pages are designed to get you to sign up or are content pages. Getting a listing on this directory won’t pass much authority to your site.
• Clearly the authority of the homepage does not transfer well to listings. The first business listing has a Host Rank 1/100^th of the homepage. Sure, you might get some eyeballs from a BBB.org listing, but I wouldn’t count on it for link building efforts.

Sporge (Domain Authority 33): http://blekko.com/ws/sporge.com+/seo

With a name like that, who wouldn’t want to be in this directory? (I’m not much for branding but I’d recommend a name-change in this case). Still, it might be worth something. Let’s see

/seo

• The Host Rank of this website is 20.2. Now you start to see the value of a linear website ranking scale- the Yahoo! Directory is 100x more authoritative that this directory.
• The geographical distribution of the backlinks is actually fairly similar to the BBB’s website. Nothing unusual here.
• Also similar to the BBB, there is a massive amount of websites co-hosted with the Sporge directory. Most of them seem benign.

/domainlinks

• Most of the links to Sporge.com come from other web directories. Could this site be part of a directory network. Is there any value of submitting to this directory as opposed to any of the others? If I submit to this directory, should I even bother to submit to any of the others linking to it?

/sitepages

• The Host Rank ends very quickly, but there’s not much authority to this website to start with in the first place. At least what little it has is able to get to the directory listings easily.

The Brick Wall (Domain Authority 22): http://blekko.com/ws/thebrickwall.com+/seo

This is the least-authoritative directory, according to SEOmoz’s list. Is it even worth the 10 minutes it would take to submit your website?

/seo

• The Host Rank is a whopping 4.3. This is another good illustration of the value of a linear ranking for websites. If you only looked at the Domain Authority of this website (as compared to Sporge- why do I blush when I say that?) you might think, “hey, that’s not so bad,” but blekko doesn't think very highly of this directory.
• The links to this site come from four “other countries.” I can’t seem to find that on my globe. This is a little fishy.
• It’s co-hosted with a few other UK-based websites. Nothing seems too bad among these websites.

/domainlinks

• There really isn’t a large number of links to this website. Where is it getting its authority (what little it does have)?
• There it is! Many of the links to this directory are reciprocal.

/sitepages

• This little directory doesn’t have much authority to share, but if it did it seems it would get to the directory listings fairly efficiently.

Now blekko’s search market share is (shall we say) still growing, but the data they provide can help you do SEO in other search engines too. As with any third-party tool, you wouldn’t want to rely on this data exclusively- obviously neither Google nor Bing are using this data to determine how they rank webpages- but this information can still be a big help to any SEO attempting to evaluate websites for potential authority and value.