Filling a need we didn't know we had until just now, a pair of developers have created a website that tracks your fill-ups in a community setting. Dubbed "Fuelly," because every web 2.0 application needs an adorably misspelled name, the site is actually quite fun and full-featured. Just add your car to the system and start tracking your mileage, how much you spend on gas, how you stack up to EPA estimates and how much you'd save by improving your mileage. Join now before weirdo dragons looking for 13-year-old cars take over the site. One of the best features of the site is that it allows you to see how your particular make and model compares to other identical vehicles. And if you're using an iPhone or other mobile device, the mobile page lets you update your mileage on the fly. Overall, we think Fuelly will work out better than our current system, which involves writing down the mileage on gas receipts and then losing them when we empty out our full wallets. [Fuelly via AB Green]
I was on the site a couple of days ago. It looked pretty good. They had my car there, with a few owners posting their milages, which seemed in line with mine.
Since all the data is volunteered by visitors, you could easily game the spreadsheet and make it seem that some cars got exceptional milages and others quite poor. Perhaps with enough people contributing this would even out, but zombie computers could overwhelm the stats.
@Maymar - now with 37% less anonymity: I used to keep an old notebook in my van's glovebox and religiously recorded every fill up, date location, brand, milage and any maintenance or repair that had happened. Wish I still had it... Now I just keep track of my trip computer to notice when milage starts to drop off, and then it's time for the maintenance.