Create an optional child element of <feed> to explicitly indicate the deletion of an entry.
Some systems cache and continue to display entries after they disappear from the "sliding window" into a feed. There is no way to tell the difference between an entry disappearing from the sliding window and an entry being deleted. In some circumstances, such as when deleting blog spam, it is highly desirable to have the entries deleted from external caches. This proposal specifies a light-weight method of explicitly indicating deletion of entries.
Add the following as a child element of <feed> (not in <head>):
x.y "atom:deletion" Element The "atom:deletion" element indicates that an entry which previously appeared in the feed has been deleted. The content of atom:deletion is the atom:id of the deleted entry. atom:feed elements MAY contain zero or more atom:deletion elements. Publishing application MAY decline to publish atom:deletion elements. Consuming applications which cache entries MAY delete the indicated entries from their caches. If they do not, they SHOULD indicate to their consumers that the entry has been deleted by the publisher. Consuming applications MUST ignore atom:deletion elements whose content indicates the atom:id of an entry from a feed other than the containing feed.
Publishing applications are not required to publish atom:deletion.
Consuming applications which cache entries would need to either delete deleted entries from their caches or store additional information to indicate that they have been deleted, and would need to have a way to indicate the deletion when displaying entries so marked.
The entry ID could be moved to a child element or an attribute.