Most runners are pretty good at guessing their distances, maybe it's a sixth sense, I don't know. But I am not most runners. And I have found myself discouraged many times when I've returned from a run and thought, "Man, that was hard, must've been like 8 miles." Then I discover it was 3. It's a little tough on the ego. So there are, of course, a host of gadgets to help runners figure out mileage (I look forward to shoes that have an implanted homing device that can be tracked from a satellite; then, you get home and look up your personalized path online to see how far you went -- yes, we might be living in a little novel called 1984, but the mapping would be worthwhile).
Anyway, because I want to get a sense of how far I'm running and because I loathe carting around any extra gadgets (like pedometers and garmin, which makes me think of a gerbil -- which sounds cute but would probably just be meddlesome on a run), I have come to love the website www.gmap-pedometer.com. For those who haven't already stumbled across it, you'd best scoot your virtual selves over there. It's very handy. Essentially, it helps you zoom into a map of your running area, and through a variety of tools, helps you track running routes. The thing that separates this site from some others is that it is specifically designed with runners in mind, so you can perform a couple of different tasks that are helpful (like saving your routes, estimating calories burned, and creating double-back routes). Plus, it can calculate distance in miles and meters (for the Canucks among us). And, I suppose, if you really want something to carry with you on your run, you're able to print the maps out and you could tuck one of those into your shoe. It's not a homing device, but I'm confident once we enter the era of the hovercraft, the homing devices will be part and parcel.