Ignore the downvotes. Unless you get more than one.
It would be nice if Upvote meant "This is good quality (whether I agree with it or not" and downvote meant "this is low quality, and should not be here, but is not spam, nor flagable". But since PG has said (something like) downvote can be simple disagreement you're going to meet people who use it for exactly that.
Also, reddit is trying to move away from "downvote to disagree" - they have a lot of hover text saying this.
I agree, but I also believe a little ambiguity and heterogeneous modes of use are actually beneficial, make the place alive.
I tend to up-vote people who make efforts and contribute important information or opinions, not necessarily those I agree with. (Will only down-vote trolls.)
It would be nice if Upvote meant "This is good quality (whether I agree with it or not" and downvote meant "this is low quality, and should not be here, but is not spam, nor flagable". But since PG has said (something like) downvote can be simple disagreement you're going to meet people who use it for exactly that.
Also, reddit is trying to move away from "downvote to disagree" - they have a lot of hover text saying this.