The "Unity Dash" in Ubuntu has always been designed around the goal of delivering relevant information to the user, but come version 13.10, due out in October, things are about to become vastly improved. With that release will come 50 brand-new "Scopes", along with a "SmartScope" filtering service. With these, users will be able to fine-tune their results like never before, and also access a bunch of information that wasn't previously possible.
Peering into a screenshot provided by the folks at OMG! Ubuntu, we can see many Scopes that should prove useful to a great number of users. While we won't list them all, the most notable ones include Wikipedia, Firefox Bookmarks, Flickr, Dictionary, SoundCloud, Social, Picasa, Google Drive, Facebook, Clementine and even deviantART. Some of these scopes are possible to run now, but 13.10 will make things easier by bundling them as default.
Also by default, each one of these Scopes appears to be enabled, which I don't believe to be the correct implementation. While a user can right-click each Scope that they don't want to be triggered to disable it, that seems tedious - especially if there are more than a handful that you don't happen to want. Ideally, users should have to enable what they want, while leaving the most basic ones enabled by default (Applications, Files & Folders, Ubuntu Software Center, et cetera). We're still months out from the final release though, so things could change.
I admit that thus far, I've been very unimpressed with Ubuntu's Unity Dash, as trying to find even a simple application (like "Terminal") right off-the-bat has been an exercise in patience. Of course, experienced users are going to better-understand how to use it, but as far as I'm concerned, the Dash simply isn't that intuitive. It's been a good while since I last gave Ubuntu a real go, however, so I'm looking forward to revisiting the distro with its 13.10 release and see where things have changed. I do have to say Canonical seems to be on the right track with these forthcoming improvements.