Backend change on My.UserLand

[dave@userland.com]

On 12/22/00 we changed the way the My.UserLand service list works. 
Now we only write out services that have changed in the last 24 
hours. It's updated at the end of each hourly scan, generally around 
10 minutes past the hour. 

We made this change because the service list was getting choked with 
channels that aren't updating regularly. 

We also optimized the aggregator so that if a channel hasn't updated 
in a week, we only check once a day. This cut the number of channels 
being scanned by a factor of 10. A worthwhile optimization.

Pointers to the various backend files are here:

http://backend.userland.com/stories/storyReader$10