Charge based on the frequency of feed refreshes
I'm new and really want to use this site as my RSS Feed Reader, but it is very slow to refresh my feeds so I can read new posts. I know you are inundated with new users and to make this site really fast will require lots of server resources. I'm used to Google Reader checking my feeds every few minutes and me noticing there are unread updates waiting to be read. So you can afford to use Cloud-based hosting and use as many servers as you need to be able to update my feeds every few minutes, I suggest that you charge a fee based on the frequency of feed updates that we see. That is, free users would have their feeds updated once each night while $10/year users see their feeds updated every hour and $100/year users see their feeds updated every 5 minutes. You would have to keep three versions of the current feeds cached so the free users wouldn't see feeds updated more than once a night or the $10/year users wouldn't see their feeds updated more often than once an hour. This might also help you on server loads since only feeds that are subscribed to by paying users need to be checked during the day and all feeds that are only used by free users are checked during the night.
Piotr Kustal commented
In addition there is a bug I guess. For example if new post is available in your feeds and you do not press "refresh" button in oldreader it won't show up. So it looks like feeds is already updated but GUI won't update itself so I have to push refresh button every 10 minutes if I wait for some important update...
Jarrad Richards commented
I agree, feed refresh frequency is one thing that will push me to another provider. This is a key function, not feature, for me. However, I won't pay a sub to get frequent refreshes. I'm not sure why people are against adverts to pay.
At the end of the day, I'll go to using an app to view my feeds before paying a sub for an online reader. And I just can't accept 24 hours for a refresh.