It took five years or more before numbers of users started to build up.
Its China project, however, could dwarf the others in numbers of users.
Facebook passed Myspace in terms of numbers of users two years ago.
If large numbers of users opt out, Google's advertising revenue would suffer.
Facebook passed Myspace in terms of numbers of users two years ago and is now approaching 700m globally.
Microsoft said it was too early to tell whether the choice screen might prompt significant numbers of users to change.
Enormous numbers of users have added the occasional enriching morsel to Wikipedia, but relatively few know how to frame their contribution in a form that lasts.
The indirect effects, he adds, include large numbers of users, the ability to learn from those users, the power of a well-known brand and user inertia.
Atlanta-based BellSouth said it would merge the two companies to create Colombia's largest cellular phone company in terms of numbers of users, with some 1.09 million subscribers.
"Social media must respect the culture and local wisdom of the country where they have large numbers of users," he said.
Twitter's inability to hit the big numbers of users and income that Facebook has so brilliantly mustered comes from the difference in its central proposition.
