Taking Blekko out for a Spin

If you’re a search engine junkie like me, you’ve probably heard about Blekko, a search engine that has been percolating for over two years and recently launched a private beta. If not, I encourage you to watch the TechCrunch video I’ve embedded above. You can join the beta by following them on Twitter. I did that earlier this week, and my invitation arrived via a direct message the next day.

Blekko’s main differentiating feature is that it supports “slashtags”. These aren’t the same as the Twitter microsyntax proposed by Chris Messina and named by Chris Blow. Rather, they are a way for users to “spin” their search results using a variety of filters. For example, [climate /liberal] and [climate /conservative] return very different results, because they are restricted to different sets of sites.

In addition to providing a set of curated slashtags, Blekko allows users to define their own slashtags by specifying the sets of sites to be included. There’s a social aspect here too: you can use (and follow) other users’ slashtags. Blekko also has some special slashtags that don’t act as site filters, e.g., /date shows recent results and /seo offers indexing information about web sites.

Blekko emphasizes two characteristics that I find very appealing: transparency and user control. While they do not disclose their relevance ranking algorithm, they do expose some of the information they use to compute it. More significantly, their emphasis on slashtags de-emphasizes default ranking, but rather encourages users to take more responsibility in the information seeking process. Very HCIR!

I like the concept. But I’m not sure how I feel about the execution. I have three main concerns.

First, the set of slashtags is somewhat haphazard–to be expected in a beta, but I’m not sure how it will evolve. I’d love to see a vocabulary collectively (and transparently) curated like Wikipedia, but I fear it will look more like social tagging site Delicious, which is a case study in the “vocabulary problem“. As any information scientist can tell you, managing vocabularies is hard!

Second, I’m not sure if site filters are the right model. What happens to sites with heterogeneous content? Or to sites that have one-hit wonders and therefore are unlikely to show up in any slashtags? I’d prefer to see the sites used as seeds to train classifiers that could then be applied to the entire index. Something a bit more like what Miles Efron implemented in this research–only on a much larger scale and applied at a page rather than site level.

Third, I think there’s a third ingredient that is essential to complement transparency and user control: guidance. As a user, I need to know what slashtags would lead me to interesting results, and ideally I’d want some kind of preview to make exploration as low-cost as possible.

I know I’m asking for a lot–especially from an ambitious startup that has just launched its private beta. But I think the stakes are high in this space, and going easy on a newcomer is no favor. I offer the tough love of a critic who would really like to see this kind of vision succeed.

By Daniel Tunkelang

High-Class Consultant.

9 replies on “Taking Blekko out for a Spin”

The second change you mention will go a long way to making this a better experience I think. Combining this idea with the /filter idea seems promising.


I think it is ethical to provide full disclosure when you write a review and there is a potential conflict of interest. Perhaps you should say “I offer the tough love of a critic who would really like to see this kind of vision succeed and who works for Google.”


Linda, I make it pretty clear that I work for Google. For example, check out and which are linked to from every page on this blog.

That said, I make it equally clear that I am representing my own views here, and not those of my employer. Besides, I’d like to think that I’m offering constructive advice that could help Blekko improve its offering.

You’re entitled to be skeptical. But I think readers here have had ample time to assess my integrity–I’ve been blogging for over two years.


Slash tag idea is interesting – and yes, puts emphasis on user. I wonder how well we will be able to externalise the slant we want.

Will Blekko offer possible slants (the way Vivisiomo used to allow you to slice results) — in which case it become a two click search.

And then could the slants by ‘curated’ by human intelligence? (And then uprank those produce by people closer to me or generally more trustworthy)?


Blekko already does offer some possible slashtags as refinements–but they’re not results-driven. But they also offer slashtags in their autocomplete suggestions–and I think that technique is much more effective, especially given users’ familiarity.

But curation is the big challenge. The personalized/social aspect is interesting, but I think the first step is assembling a robust vocabulary that addresses the needs of most users. Wikipedia really is a great model here, but there’s a lot of work between recognizing a model and replicating its success.


Blekko is definitely a cool new search engine. The slash tag feature is unique and gives it an edge that people will be interested in. However, I do not think it will ever reach the popularity of Google due to it’s complicated nature. I think Google’s greatest strengths is it’s simplicity; it’s so easy anyone can use it to it’s full potential. Blekko is not like that.

Coming from someone who doesn’t have a lot of time on her hands, having to learn how to use a search engine does not appeal to me when I have Google available. Of course I took the time to learn about Blekko, but I’m in the industry. I don’t think the average person will want to do that.

I’ve done some research and I think the best new search engine is Bweezy. Similar name, but very different from Blekko. Bweezy offers Google results, which I love. It also lets you open search results in the same window as the search, which eliminates the need to open a ton of tabs! I’d check it out if you’re into new search engines.


Comments are closed.