It's a solid technique. I did the exact same thing for a news site I started with comments on articles and the forum. No one wants to hang around a 'dead' site

It's a solid technique. I did the exact same thing for a news site I started with comments on articles and the forum. No one wants to hang around a 'dead' site, but post enough activity, post enough 'controversial' comments and people will want to join in, and then suddenly you have an actual ecosystem of real people driving traffic.