The Slashtags concept looks awesome, and as buzzwordy as it sounds, adding a social aspect to search by allowing Slashtag sharing could really take off. For example, a lecturer could put make a /thiscourseonly Slashtag, searching only hand picked sources.
What would be especially great is a smart form of autocomplete. Eg once you typed /date you would get dd/mm/yy or dd monthname year or similar ghosting in front of the cursor.
The only concern would be that Google and Bing could copy it fairly quickly, so hopefully their other features are strong enough.
As they VC query used to go: "is this a feature or a company?" So far Blekko looks like a feature, but I will reserve judgement until I can actually play with it a bit. I really hope that this slashtags bit is not the only interesting thing they have to show after several years of work. OTOH, this does fit what seems to be a pattern for Rich Skrenta and his team: find an already occupied niche and crank out something that has 60-70% of the polish of the leader with a few new features and then flip the whole thing to someone who is desperate to get in or stay in the game.
In a sense, Google already has something like this, the Custom Search Engine: http://www.google.com/cse/ - the interface is a little different though, you create a "search engine" which has something like the slashtags built in, rather than specifying a slashtag as part of the query. Has it's pros and cons.
What would be especially great is a smart form of autocomplete. Eg once you typed /date you would get dd/mm/yy or dd monthname year or similar ghosting in front of the cursor.
The only concern would be that Google and Bing could copy it fairly quickly, so hopefully their other features are strong enough.