Link: https://code.launchpad.net/~edb/quam-plures/notify_with_excerpt
If subscriptions is enabled the subscriber will always get the entire post in email. Seems to me we should be able to offer different settings for what gets sent. The whole article, an excerpt, or maybe just the fact that there is an article to see. This branch addresses that issue.
UPDATE: branch merged into core on 2011-03-14. Superb!
