The Core

Blekko Expands: Bigger Index, More Slashtags & New Design
http://selnd.com/vviPlb

I've not put it to any test, but Blekko did need more depth and more long tail results.  At least they are trying.

All my sites rank top in Blekko.  If only there was a demand for a Blekko SEO expert 

I think outside of the US it was missing huge amounts of sites/data. It'll be interesting to look again if they now have an expanded crawl. Although I guess that may not be reflected in links etc immediately.

I assume the expansion comes from infusion of Yandex funds.  I hope it helps them expand their index, and perhaps shake up some internal philosophy too.  We really don't have many other alternatives.  

I think outside of the US it was missing huge amounts of sites/data.

I've felt that inside the US, it was missing huge amounts of sites/data too.  When I asked a Blekko booth guy about this a while back, he said... very self-righteously... that that's because they don't index spam.  It was hard to have much of a discussion beyond that, except to suggest that not all that was missing was spam.  There's also zero documentation for a lot of Blekko features.  

All that said, I've liked some of Blekko's search and SEO data, and it's led me to information I wouldn't have found otherwise, but I can't rely on them for day to day search.  I haven't run any major tests since the announcement of the expansion.  What I have tried hasn't shown a major change.  I'd like them to achieve enough critical mass to be a useful tool.