I know that officially identical requests cannot be done in more than one minute.
But would it be a problem if I had a server which had a list of question IDs (say 10 per user, so reasonable max 10,000 in total) and the server polls the API every minute each question with a pagesize of 0 just to get the number of answers and see if any are new?
Eg: http://api.stackoverflow.com/1.1/questions/2366/answers?pagesize=0
(so basically 100s or 1000s of different requests every minute or 2?)