Saying "It can or should be answered" is not the same thing as saying "Good question".  
  
How do I optimize my disk performance?  
  
vs  
  
https://askubuntu.com/questions/252140/how-do-i-install-and-use-flashcache-bcache-to-cache-hdd-to-ssd

I might answer the first, but I would *and did* upvote the second.
  
An additional note after some discussion in comments is that some voters in an attempt to "keep it fair" don't vote on anything they answer.