Single Servings

I love the new(ish) trend of tightly-focussed websites that do only one thing. Some of these "single-serving" sites are just silly, but others are incredibly useful. My longtime favorite is Down for everyone or just me?, which can tell you whether your trouble reaching a website is at your end our theirs. My latest discovery (via Kottke, as I recall) is priceofastamp.com. I mail things rarely enough that I never seem to know what the current first-class postage is. I know I could search, but that's so much trouble.