You can't deny what you've been up to online. We have the data.

We know what you’ve been doing on your computer. You’ve been Facebooking and Tweeting up a storm, haven’t you? You can’t deny it. Nielsen has the proof.

If you’re anything like the average social-networking user, you spent a little more than 5.5 hours total on Facebook and Twitter in December. That’s an enormous 82% bump from that same time last year. Facebook has swelled to about 206.9 million users. That means that Facebook’s population is larger than that of most nations. There are more people on Facebook than in Russia. And Canada. Combined. As for us, a little less than half the United States is currently on Facebook right now at 142.1 million unique visitors. We’re closely followed by Japan at 46.5 million social network users and Brazil with 31.3 million. The top honor for most time spent online goes to Australia at 7 hours a month.

What does this mean? It means that perhaps Facebook should get a chair at the UN. With all seriousness, it obviously means that there’s an enormous, growing user base that just about anyone can reach. However, unlike some forms of advertising, social networking requires companies to develop a message that isn’t self-centered — as most traditional marketing messages are. Because social networking users must voluntarily subscribe to each particular organization’s message, marketers must create a conversation that’s both informative and interesting. Therein lies the most difficult and perplexing problem most companies encounter in trying to reach all these Facebookers and Tweeple.