Yes. Other search engines are indexing us as well. Roughly a third of our traffic here comes from web crawlers (bots for search engines that index the site).
Google’s mysterious “algorithm” is to blame. The Straight Dope used to be profitable due to advertising, but then Google changed their algorithm and that profitability went away overnight. Google doesn’t publish the details about how their algorithm works, because it’s a trade secret and because they don’t want spammers and such to game the system. They do give some hints. One big hint was that they would drop you significantly in the page rankings if your site was not what their algorithm determined to be mobile friendly. Changing the default theme to the much-hated Sultanstheme on vBulletin was done specifically to address that, and while Sultans-hated-theme did satisfy Google’s algorithm at least for the mobile-friendly bit, other changes to the algorithm have left us so far down in the page rankings that we’re no longer profitable. I’m not involved in the financial side of things here so I don’t know what other things were tried to improve our rankings. All I know is that they were all ultimately unsuccessful, which forced the end of the Straight Dope columns. To this day, we still rank very poorly in Google’s algorithm. Why? Who knows. It’s not because other sources exist now, because we used to compete very well against those other sources. Just one day we’re ranking fine, the next day we’re not. Thanks, Google.