I'd like to view all the questions with my interesting tags at once. Is it possible? If not, I vote to implement it :D.
I guess at the moment it would only be possible through a new tab or a search with the tag list. A button to trigger a search could be added right next to the Interesting tags title, I would suppose.
The interested tags for now are used to color code questions using these tags on the client side. This would make it hard to sort. You can see this if you have ignored tags: they just reduce the number of tags shown on the page. A sort option would only bring up the marked questions for this page, not the whole search.
There is a possibility to see only questions concerning your interested tags, but only unanswered ones, where an unansweredquestion has 0..n answers without upvote and no accepted answer. Just choose the 'unanswered' tab and there 'My Tags'.
Well, if it's a small number of tags, you could do a normal search but include your tag names in [brackets].
I agree though, there should be a toggle to sort by "questions with all of these tags" or "questions with one or more of these tags." It'd make the feature more useful I suppose.