Blizzard recently ended their "Ask the Devs" series of community interaction. In Ask the Devs, the community posted questions and the questions were voted on. The 10 or so questions with the top ratings for each topic were resented to the devs and the devs gave answers.
It was an interesting exercise in community management. However, Ask the Devs is generally regarded as unsucessful by both the Blizzard CMs and the community.
Let's take a look at why Ask the Devs failed. It was a worthwhile experiment, but I think that there are two major reasons why it failed.
First, the vast majority of questions were thinly-veiled versions of, "My class sucks. When will you buff my class?"
That was not conducive to interesting answers.
The second reason is that asking good questions is just plain hard. A lot of the time, it is difficult to ask a good question unless you already know the answer.
For example, let's take a question like, "Is Blizzard planning to change the paladin healing model?" If the answer is No, this was a very pointless question. But if the answer is Yes (as in pre-4.0), all of a sudden the question is extremely interesting.
But the playerbase doesn't really have enough information to know which are the interesting questions and which are the boring questions.
This was the biggest strength of the previous interaction between Ghostcrawler and the forums. Because Ghostcrawler knew the answers, he also knew which questions were worth answering.
Of course, that model was not sustainable, and Ghostcrawler's presence on the forums tended to warp them, as everyone started trolling for blue responses.
The new form of Dev interaction, the development blog posts, also have weaknesses. In particular, they have a tendency to be at "too high a level". Ten thousand foot overviews are generally not interesting. Specifics are interesting. The best Dev blog was probably Ghostcrawler's line-by-line explanation of the patch notes, which was about as specific as you can get. Even the ten thousand foot overviews can be greatly improved with concrete examples.
But dev blogs are probably an art, and something that needs to be learned. The gold standard of gaming dev blogs, in my opinion, is Mark Rosewater's columns for Magic: the Gathering. A dev looking to communicate with her game's community would probably be well served by studying how Rosewater did things.