Add “I have this problem too” flag
I'd like to see a button strictly for people that have/had the same question. Such questions would gain more weight as time progresses. Hopefully, experts could zero in on those questions. These upvotes would not require changes in reputation (unless you have something like +2 reputation for getting 10 such votes). People that mark questions accordingly could have the option of subscribing to the question.
I don't find the current question upvote specific enough to this purpose. It would also help alleviate the issue of extraneous "I have the same question" type comments.
I am aware that some members have suggested using the current upvote for this purpose... but I'm thinking in terms of non-members coming in directly from Google.