Still, "None of this really matters until Facebook goes public," ReadWriteWeb reminds us. "This isn't the first time we've seen reports regarding Facebook's supposed valuation ... In March, for example, The Wall St. Journal talked to several investors who were anticipating a market capitalization of $35 to $40 billion for the social network, given a 2011 IPO."
Calling such lofty valuations "risky," Mashable warns: "One only needs to look back at MySpace and how quickly it fell from a social networking powerhouse to a has-been."
While downplaying the numbers as "fundamentally speculative," Facebook sources are predicting sales of at least $1.4 billion this year -- up from about $800 million last year. By comparison, eBay's revenue is expected to top $9 billion this year, Mashable notes.
Yet, just based on those privately-disclosed numbers, analysts believe that Facebook has put an end to any remaining marketer concerns about social media. Citigroup analyst Mark Mahaney tells Bloomberg: "As an advertising platform, Facebook has been proven."