Are you familiar with the centralized exchanges like Poloniex or Bittrex?

In part, Openledger works in the same way. When you deposit BTC with Poloniex, it goes into some wallet that's controlled by Poloniex. They have a database which tells them how much of their BTC belongs to you, and then they basically give you an IOU that you can trade on the Poloniex exchanges.

With Openledger, you deposit BTC and it goes into their wallet. Just like how Poloniex has a database which tells them how much of the BTC belongs to you, Openledger also has such a database - but their database is the Bitshares blockchain itself. The way they track how much of the BTC belongs to you is that they issue you an equivalent number of OPEN.BTC tokens.

So Openledger keeps the BTC that you deposit, and I suspect it's auditable in some way but I've never tried.

What's the point of a multisig if the "owner key" can just undo it all and spend on its own?

You can multisig owner permissions as well.

The big smartcoins all seem to have a parameter called "force settlement offset" set to 1%. What is this? Does it mean that you get only 99% of the face-value BTS when you request a settlement?

If so, what is the purpose of this?

DACplay has some news: it is going to be worked based on the Ethereum.

Interesting. Where is this news available?

There are some post on steemit that are supposedly from the slack channel. I can link that later. Have you checked out museblockchain.com? It looks like work is being done but it's very slow going

Well, don't get me wrong - I'd love for this to be legit. I've had high hopes for Peertracks for a long time.

Would it be safer to create a new Bitshares account and
transfer your bitshares to that account? Then use the
private key of the original (now empty) account to claim
your Peerplays. If that private key gets compromised/revealed
to a third-party it doesn't really matter because the account
it controls is now empty.

That would certainly work if you're not too in love with your original account. There is better way to do it, but I haven't dug enough yet to be sure I know what that way is.

I believe you have to add a new (2nd) key, then you'll be able to delete the original one.

One question I have is how to generate the new 2nd key. The web wallet doesn't seem to be giving me the option anywhere.