How does miner voting work? I always here people talk about miners being able to "vote" on certain things using the block chain. So here are my questions:

1) who gets to ask the questions?

2) what type of questions are being asked?

3) do they "vote" by selectively solving one block?

4) how is it even possible for even the biggest miners to selectively solve a block when the hash rate is so high? 

5) does question #4 propose a vulnerability in the network?

Thanks. I never really understood this aspect of mining regarding big time mining farms
I'll try to answer your questions specifically, but here's a good read on how Bitcoin votes on upgrades.

1) The questions are really all the same question:  which BIPs do you support?  These proposals make their way through the Bitcoin development community, and once implemented, can be voted on by miners.  So basically, anyone can make a proposal.

2) See the answer to question 1

3) No

4) Since the answer to question 3 is "No", this question makes no sense.

5) See questions 3 and 4

EDIT:  I changed the link explaining BIP voting to one with less bias and opinion, and is much more concise an explanation.