I've been using it for about the last year or so and have found it easy to use, too. FWIW, I'm here.

One quirk I noticed while traveling in Southeast Asia and Australia: I put my travel dates in, but the status updates ("jackal is leaving Singapore today," "jackal arrived in Sydney," etc.) were delayed almost a whole day. My guess is the statuses update at midnight whatever time it is where the Dopplr servers are, whereas it would be a better design to do the updates at midnight in whatever the actual destination time zone is.

Still fun and useful to announce where you are and where you're headed: I haven't run into anyone I know yet (I only have a couple people linked on Dopplr itself), but I do have it set to post my travels to Facebook (and keep all my friends there apprised of my jet-setting! )...