"Facebook first leased 11,000 square feet on the sixth floor of the glass birthday cake-shaped
building, wherein the Office of the Comptroller of the Currency was also housed," Betabeat explains. Facebook later relocated to another Madison Avenue address. Now, "With the world's two most
powerful social media companies just blocks from one another, for better or for worse, it seems only a matter of seconds before the classy office strip is dubbed Silicon Avenue (there, done)."
According to Betabeat, Twitter has set up a temporary home base in Soho back in November, and has since been looking for something more long term.