I work in search quality at Google, and it's really exciting for me to see a result that another search engine returns that I don't understand. It inspires me to think of all the ways they might have returned it, and leads to a lot of neat ideas. For the same reason, I enjoy reading the reaction in the SEO community to major changes to Google's rankings. Sometimes we're too close to a change to see what it does effectively instead of in principle. What the SEOs conclude often ends up being a really good first-order approximation of an unintended side-effect.
If you believe that your competitors are doing incredible things, it's a great inspiration to try doing incredible things yourself, regardless of whether you're right about what they're doing.
Give DuckDuckGo a try for a couple of weeks, you probably won't go back to whichever search engine you are using currently :-)
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.
The best way to get an invite is hit us on twitter or facebook (see links from blekko.com). Then we can DM you an invite when we have them ready.
This is a great differentiator from Google. Google can copy features like slashtags easier, but I can't imagine a large company known for its secrecy suddenly exposing their algorithms.
http://duckduckgo.com/bang.html and http://duckduckgo.com/goodies.html
Right now your only source of ranking data straight from a search engine is Yahoo's Site Explorer, and even that data is quite limited and its future availability uncertain. I've never seen duplicate content exposed so openly.
And as ora600 said, that level of transparency is something Google exceedingly unlikely to copy.
Third party developers could even get paid via ads that appear whenever their algorithms are used in the search results.
