Suggest you read the Wikipost at the top of this thread
http://www.flyertalk.com/forum/manuf...amex-blue.html
Note that:
1. Rewards are posted one month after the statement in which they were earned.
2. The list of eligible Drug Stores is short.
3. American Express does not classify merchants. They are classified by their
acquirer, the company which processes their card transactions. You can see how a specific transaction was classified by viewing transactions online and clicking + symbol to view the transaction details.
4. American Express did have a problem correctly crediting Supermarket transactions. This seems to have affected various cards:
http://www.flyertalk.com/forum/ameri...er-2013-a.html