|”If you had in-place purchase flows, do you think |users would feel comfortable entering the credit |card?”

not normally, not now. but ideally, we will eventually get to that point where your one-click purchase is a web-wide standard, not just a site-wide feature (ie. amazon.com).
whether or not is is client(web browser) or cloud based… or a mix… we’ll see.
i do anticipate there being a “pay with twitter” in the mix. maybe sooner than later. wouldnt still have some bouncing back and forth pay-pal style though. but i know its possible to do cross-domain ajax. ive done it with flash, javascript and a crossdomain.xml setup. i also know that as part of the html5 draft, it is achievable through supporting browsers, natively.

so we should see improvements in this area.
and when we do, everyone wins.