I'bles has already excluded URLs from the new Google search harvester Answered
UPDATE: A long time ago, I wrote:
The new Google search has some nice features, and some not so nice ones. Besides the obvious (unsortable, hard to filter, etc.), there's one really annoying bug. If you search for words which appear in the titles of Instructables, you get a bunch of hits for the auto-generated "e-mail" pages. For example, note the third hit.
In my opinion, URLs containing "email?" should be excluded from the search database, the same way that URLs containing "edit?" and "/search/" are.
In the intervening time, it's pretty clear that the intrepid Instructables Staff has already resolved this bug.