It's true that if you have just a few readers you may need to be patient. (Figure something like 5-10% response rate if they are pretty loyal readers.) Still, it's a good habit to get into, ie, checking in with readers on your content.

I agree with Mark that an incentive may help. But it's not always necessary. The key is to set your expectation at the right level.

If you go to a party where you don't know anyone, you'd probably expect to have several good conversations. Your first polls/surveys may well be the same. But by going through the process and teaching your readers that you are interested in what they have to say, you'll grow the relationships.

Andy