Now that Google has officially taken the training wheels off Google+ and opened it up to everyone, it's advertising the social network on the world's largest digital billboard: Google.com. The blue arrow you see above, pointing at a link to Google+, is actually drawn on the homepage today. (It's visible on most browsers, though not all.) With more than 25 million users, Google+ has already put up impressive numbers, which are bound to skyrocket with such visible placement now that the site has officially come out of invite-only beta. However, some industry observers are skeptical that Google+ will find mass appeal, given reports that traffic and time on site had begun to slump in late August. I'd argue that today's promotion is exactly what Google+ needs: prompting a massive injection of new users. The biggest beef I've heard about the network is that it often feels vacant of "real-life friends" and instead has felt like the playground of self-promoters and other early adopters. What do you think? Will this not-so-subtle promotional move help make Google+ the social-network second coming that so many prophesied it to be?