Recently I got a Nexus One, which had me curi­ous to dis­cover the value (if any) of location-sharing appli­ca­tions like Foursquare and Gowalla. I had dor­mant accounts for both, and decided to see who among my con­tacts were actu­ally using these things. I imag­ined not many.

Foursquare’s friend finder was straight­for­ward and I was able to add three or four peo­ple. Gowalla’s, on the other hand, mis­led me into send­ing an invite to all 947 peo­ple in my Google con­tacts. This includes peo­ple I bought stuff from on Craigslist; old bosses; old girl­friends; co-workers; prob­a­bly even prospec­tive employers.

The trick was in mim­ic­k­ing a fairly stan­dard “Step 2″ for­mat for these types of func­tions. It appears that I’m being pre­sented two choices here: the first, to begin fol­low­ing only those con­tacts who are already on Gowalla; the sec­ond, to send invite emails to all checked names in the list.

Instead, both but­tons do exactly the same thing. So when I clicked the but­ton at the top, an email was sent to every per­son on that list. There was no pop-up win­dow telling me, “You are about to send an email to 947 peo­ple. Continue?”

For­tu­nately I hadn’t used my full name on my pro­file; the email peo­ple received came from no-reply@gowalla.com or some­thing sim­i­lar; and I deleted my pro­file as soon as I real­ized what had hap­pened. So hope­fully I wasn’t as incrim­i­nated as I may have oth­er­wise been. I know I roll my eyes when­ever a friend has fallen for an obvi­ous trap like that. And I like to think I’m pretty good at spot­ting these tricks. But this lay­out is out­right deceptive.