Traveling This Summer? Int'l Tipping Etiquette
Tipping customs vary greatly by country and by profession (see the Freakonomics post here about why flight attendants don't get tipped), see some International tipping guidelines from the BBC here, which includes these tipping customs ranging from no tipping for anything, to tipping for almost everything:
No tipping of any kind is expected in Australia, China, Japan and New Zealand.
No tipping is expected at restaurants in Italy and France (service of 15% is included by law in France).
In UK pubs, you don't tip with cash, you offer to buy the bartender a drink.
In Egypt and Mexico, you are expected to tip for almost everything.
(HT: Sanil Kori)