Calling Renren (NYSE:RENN) the Facebook (NASDAQ:FB) of China didn't used to be fair because China's leading social networking website operator was growing a lot faster than Mark Zuckerberg's global juggernaut.

That may no longer be the case.

Renren reports tomorrow afternoon, and the market's holding out for surprisingly lackluster top-line growth. Analysts see Renren's quarterly deficit widening to $0.07 a share with revenue climbing 23% to $55 million. For those scoring at home, Facebook came through with a scintillating 53% surge in revenue as it effectively monetizes the booming mobile usage of its sticky app.

The good news for Renren investors is that this is just a lull. It grew at a 41% clip during this year's first quarter, and analysts see its top line climbing 36% for all of 2013 and yet again in 2014. However, did anyone think that we'd see a quarter where Facebook is growing twice as fast as Renren?

Renren has already distanced itself from the Facebook comparisons, and not just because Facebook reclaimed its $38 IPO price this month while Renren trades considerably below its 2011 IPO price of $14.

Renren's growth has come through online games and its daily deals site Nuomi. In fact, online advertising now accounts for just 21% of the revenue at Renren, and it grew at a surprisingly weak 5% clip during the first quarter. It's an entirely different scene at Facebook, where online advertising now accounts for 88% of the business.

In that regard, Renren may actually be a closer match to Zynga (NASDAQ:ZNGA) since it relied on Internet games for 57% of its revenue in its latest quarter. Then again, it wouldn't be fair to call Renren the Zynga of China, because there are so many other larger players catering to young gamers in the world's most populous nation.

Then again, Zynga and Renren do have one embarrassing thing in common: Both stocks happen to be trading well off their 2011 IPO prices.

Renren can naturally change the market's negative perception when it reports tomorrow. It can silence the naysayers, and they're certainly out there. There were 6.2 million shares of Renren sold short at the end of July. That may not seem like a big number, but it's actually more than doubled in four months.

Asking if Renren is the Facebook of China or the Zynga of China is irrelevant. The question that matters for investors is when Renren will bounce back.