For what it’s worth, Slate’s Will Oremus is finally ready to admit that Twitter -- and the vibrant culture of tweeting, retweeing, and following others on the social network -- is no fad. Yes, “New figures make it clear that the 6-year-old microblogging site has lived up to its billing as the biggest thing to hit the Internet since Facebook,” Oremus admits. Twitter announced this week that it has reached 200 million monthly active users worldwide.