I'm interested to see this podping service, however given the whole model of RSS is that the end-user is requesting feed updates (I would guess daily on average, but maybe hourly?), I have a hard time thinking this was a problem for podcast providers. I have no knowledge of the implementation at scale, but given the feed is static for the most part, wouldn't podcast hosting providers want their users constantly checking in?
Depends on the podcast and the users. If I know my favorite afternoon commute podcast drops at 4:30 PM local and I don't see it by 4:45 PM, I'm going to be doing the pull-to-refresh thing frequently, hoping it's available to download before I leave the WiFi at work for my drive home. I suppose Podping plus push notification to all app installs subscribed to the podcast that just updated would be another way to do it.
