My situation was a little different. When Linuxworld.com launched back in '98 or so, it was it's own site and didn't redirect to networkworld.com. Not too long after launch they made user registrations available. For some reason I was screwing with the URL in the address bar and accidentally hit enter.. they had left 'directory browsing' enabled and stored the username/email/password list in clear text inside the webroot.
I emailed them and didn't get a response. The next day I emailed them the list and within an hour they disabled all user registrations, the feature was completely removed from the website but still didn't ever get a response.
I never visited the site that much so I have no idea if they ever went back to it, but I still can't believe someone would develop something that stored passwords, email adresses and usernames in clear text in a flat file, inside the webroot.