This is how my url looks be:
https://www.google.com/reader/api/0/mark-all-as-read?s=http://www.campionatoseriea.net&ts=1345114937
I can't understand why it doesn't work! I'm successfully logged in.
* EDIT *
https://www.google.com/reader/api/0/mark-all-as-read?s=feed/http://www.campionatoseriea.net/feed&ts=1346843394
I tried also this query but it doesn't work!
Try including the token parameter (T).
https://www.google.com/reader/api/0/mark-all-as-read?s=feed/http://www.campionatoseriea.net/feed&ts=1346843394&T=//cDr2ct8ynZS2I-P4x4cn1A
This document describes how to get a token.