I'm only comfortable giving away my posting key. With it someone can post and upvote in my name. Already https://www.steemengine.net/ has used my key to upvote themselves without my permission.
I was on @DLive yesterday and I wanted to use the chat window. They asked me to log in with my active or owner key. Ridiculous! First of all no one should ever ask you for your owner key, ever.
I guess selling your account would be the only reason to give out your owner key freely. Then again, who would ever buy a Steem account? Not only would you have to control the owner key, but you'd have to control the email and phone number attached to it as well.
Secondly, I technically shouldn't need to give any key to chat on DLive. It isn't posting or upvoting. At most they should ask for a posting key to confirm that people aren't running around impersonating other accounts. However, there are other ways to do this without giving away your key, like posting or transferring 0.001 SBD.
This is a good example of how new and rapidly changing everything here on Steem is. Always be mindful of which keys you choose to give to which third parties. I'm personally only giving away my posting key. I see no reason to let someone transfer SBD from my account.