Yes. In this case they are so far using the keys for voting only. What they'll use the keys for in the future we don't know. All the hackers are different and do different things with the accounts; we're just lucky this one only likes to vote versus spam.

If you've ever used a voting site called 'steemengine' (not to be confused with the new steem engine which creates tokens and tribes) then the keys are compromised. If you never used that site and are just maybe using a trail, then it's whatever you're trailing that's compromised and not you. We can't tell based on just transactions, which is why we're going the route of warning everyone.