Individual subscriptions can now be enabled / disabled from the subscription properties page.

If the feed supports PubSubHubbub, then yes - else it'll fall back to an hourly check.

That's a good suggestion, definitely one for the list!

I think that's an excellent idea, and is on the TODO list now.

We've got similar functionality on the TODO list, but I didn't know about that fulltextrssfeed.com - I'll have a look into that!

Whoops, last minute gremlin there ;)  You should be good to go now.

The migration tool is in place now, and can be found in 'My Subscriptions'.

A migration tool is in the works and should be available within the next week, which will allow you to move any existing subscriptions into the beta.