Hehe you beat us to the announcement post, we’ve been operating in a stealth soft launch style.

Regarding your question :

You can choose which key you enter in Keychain, posting, active or owner.
Neosteem request your active key, I don’t know why and @thecryptodrive will probably answer this question.

Yes I will answer it, so each key has a different level of authority, you only load the ones you need. You are unlikely to ever need an owner key on Steem Keychain, keep that safely locked away.

Posting key you will need for everything, voting, posting, commenting etc

Active key you will need to do transfers of steem and sbd. You will also need it to authorise an account to have posting authority as is required on TokenBB.

So start with posting and active key, after authorising with active key you can remove it from Steem Keychain if you don’t plan to use it for transfers or authorise any other app.