by Irina Slutsky, AdAge.com

NEW YORK — More than a million websites around the web are looped into the world’s largest social network via Facebook Connect. Its social plug-in — the increasingly ubiquitous “Like” button — generates at least 3 billion clicks a day. And for many brands, a Facebook presence has outstripped their own web sites. With Facebook providing sharing tools, authentication, and even commerce for so many sites and brands, what happens when Facebook goes down, as it did on Sept. 22 for more than two hours?

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