I'm the co-writer of an addon updater called Waddu.
We have some problem of updating addons from Your sites. Currently we have to download and parse addon info pages to get informations about an addon.
All multi-site updaters have to use this method, 'cause the sites have no public XML API interface to get addon informations. If You publish a public-useable interface to get addon informations (addon name, authors, current version and update time, etc), we will change our updater to use this to save much more bandwidth.
Please help us.