@mcg @rishabh You can alternatively use "email@example.com" to avoid the validation issues with using a + symbol. If you use labels instead of folders, this method also automatically labels the message with the "something" label. The other method is supposed to create labels, too, but that didn't work in my experiments.
Fastmail isn't encrypted, and its servers are in the United States. So if I ever commit treason, my emails will be accessible by warrant. So far, that's the only thing I would like to see added; everything else—the interface, the features, the pricing—is really fantastic. Of course, I'm not planning to commit treason and I have nothing to hide, but it's the principle of the matter, especially now that a senator from my own state has filed legislation to outlaw encryption altogether.