Ok that sounds like an idea - but when one user used the specific answer to solve the problem -> gives upvote -> ok
The user who upvoted the answer because it helped him/her, is confronted again with the same or similar problem - he/she already knows the solution because he/she solved the problem before.
Maybe the user should than just write a comment to the useful answer that he/she could solve the similar problem and describe the problem -> would be helpful for search.
I understand your way of thinking but that isn't a solution in our situation. We use the questions/answer system to provide information to the Support team. If it is possible to provide multiple upvotes we can also monitor the occurrence without counting the number of comments.