It would be nice to know, more or less, what is the expertise base that we have on Engineering SE.
Instead of each person giving a separate answer akin to "Hi, I'm an X engineer", where X is their expertise, perhaps we can set it up like a poll: one separate answer per expertise and people upvote it if they have the same expertise.
For example, i'm an applied mathematician. So i would post the answer: "applied mathematics". If you are also in applied math, you would upvote my answer instead of duplicating it. If you are something else that isn't already listed, answer with your particular expertise.