* Enterprise customers deploying hundreds or thousands of desktops. They will love this feature, because it will allow them to customize which external and internal online sources employees will be able to search, and then they will be able to track all employee searches.
* Regular people -- that is, the kind of people who don't even know about HN. These people will also love non-local search in the Dash. They already search for everything on Google, buy everything through Amazon, and readily hand over all their intimate, personal information to FaceBook... without ever giving their own privacy a second thought.
* Power users who're aware of the privacy issues involved. Virtually everyone in this market segment, including me, feels strongly that non-local search should be offered only as an opt-in feature, if at all.
Viewed in this light, Canonical's decision to implement non-local search can at least be understood: they're trying to make their customers happy, but they've unintentionally pissed off the smallest of the three market segments above: power users. (Sorry for the harsh language; I can think of no better way to convey how a lot of Ubuntu power users feel about this.) Alas, power users may be the smallest of the three market segments above, but they have disproportionate influence over the other two. Disregarding the concerns of power users may not be a good idea in the long run.
In retrospect, Canonical could have -- indeed, should have -- handled the announcement of this feature much better. There was really no announcement; the news was just 'dumped' on the community on a third-party blog. Is this really how Canonical wants to treat power users?