Social media giant Facebook has one major catalyst that makes its stock a "buy," Brian Pitz of Jeffries said Thursday.

"We think video ads could be next billion-dollar business," he said, noting that advertisers want more than Google to buy from. "We believe Facebook's very well positioned to be that No. 2 player."

On CNBC's "Fast Money," the internet analyst noted that Google had bought YouTube when it had no revenue, whereas now he estimated the online search engine would see $4.5 billion in revenue for 2013.

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"When you look at video, both on desktop as well as on mobile, it's one of the best-performing ad formats, not only from a volume perspective but also from a pricing perspective," Pitz said.

(Read More: Why It Might Be Time to 'Defriend' Facebook)

Shares of Facebook gained more than 5 percent to close at $24.55.

Trader disclosure: On May 30, 2013, the following stocks and commodities mentioned or intended to be mentioned on CNBC's "Fast Money" were owned by the "Fast Money" traders: Guy Adami is long C; Guy Adami is long GS; Guy Adami is long INTC; Guy Adami is long AGU; Guy Adami is long MSFT; Guy Adami is long NUE; Guy Adami is long BTU; Karen Finerman is long AAPL; Karen Finerman is long BAC; Karen Finerman is long C; Karen Finerman is long JPM; Karen Finerman is long GOOG; Karen Finerman is long JCP PUTS; Karen Finerman is long GM; Karen Finerman is short SPY; Karen Finerman is long MDY Puts; Jon Najarian is long AAPL ; Jon Najarian is long JPM; Jon Najarian is long FSLR; Jon Najarian is long TSLA; Jon Najarian is long EMC; Jon Najarian is long JOY; Jon Najarian is long ALTR; Jon Najarian is long COP; Jon Najarian is long GRPN; Jon Najarian is long HL; Jon Najarian is long OC; Jon Najarian is long TMO; Brian Kelly is long TLT; Brian Kelly is long YEN; Brian Kelly is short S&P Futures; Brian Kelly is short NIKKEI.