Get changes on server without polling every object

[honkmaster]

There should be a possibility to get the changes on the server without polling every current object of a specific category. Expample: An user has 1000 Mails. He deletes Mail 999 on the stud.ip website. The App can not request every 999 mail, compare them to the 1000 that are stored locally and then delete the one that is not in the 999 on the server. This is a performance catastrophe! I image something like:

Route /messages/changesSince/20121110 with the return:

{
123456789,
abcdefghij
}

So i get a list with every object that has changed since 10.11.2012 and has to be updated locally.