Amazon’s Kindle Fire is running even with Samsung’s Galaxy Tab in terms of app sessions, according to mobile analytics company Flurry. The results underscore much of the evidence we’ve seen thus far that the tablet market is becoming bifurcated between Google’s official Android Market and Amazon’s upstart appstore.

“Remarkably, and from a standing start, the Kindle Fire overtook the Galaxy Tab in just a few short months,” wrote Flurry’s vice president of marketing Peter Farago. The Fire recently overtook the Tab in app sessions with a 35.7 percent share to Samsung’s 35.6 percent share. With Amazon capturing this much momentum over the holidays, it would be easy to see them eating up more market share going into the first quarter. That said, there’s still a rising tide with overall Android tablet sessions tripling from November.

Flurry didn’t reveal exact device counts for either the Fire or the Tab. Farago told us, “We made the decision to avoid releasing hardware numbers. We let the big boys release their own,” referring to the time the company famously angered Apple by revealing early stats on the then-unlaunched iPad.

Secondly, Amazon seems to also be better at supporting paid downloads than Google’s Android Market. Flurry looked at five paid apps that ranked in the top 10 over the past month. The Fire was able to push 2.5 times as many downloads to this sample of five paid apps compared to the Galaxy Tab. Android Market has had problems with paid downloads for more than a year because Google doesn’t have as much readily available credit card information on its own users. 

“This shows that for tablets, the Amazon App Store can already deliver more direct revenue to developers than the Android Market,” Farago said. “Even more impressive is that the Galaxy Tab, launched in November 2010, has a much larger existing installed base than the newly launched Kindle Fire.” Flurry believes there are twice as many Galaxy Tabs in circulation as the Kindle Fire.

Flurry says there are a handful of reasons why Amazon might be performing better on driving paid downloads:

1. Amazon gets content. It signed deals with Rovio and Facebook to have apps ready to go from the beginning.
2. It has payments data on millions of consumers already and isn’t starting from a small base like Google must. “Upon launching the Kindle Fire, consumers must either link to their Amazon account or enter credit card information,” Farago writes. “This makes the user base 100 percent payment enabled.”
3. Amazon is also willing to take low or no profits on device sales for market share. It’s ”the ultimate razor-razorblade model, where the “stalk” (tablets) is given away for as little as possible and profits are made from the sale of razors (content).”

We’re also hearing that Amazon is performing better on an ARPU (average revenue per user) basis for freemium apps than Android Market. Crowdstar chief executive Peter Relan told us last month that Amazon’s user monetize four to five times better than ones from Android Market.

What this means for developers is that if they want to be a part of the Android tablet market, they now have to take Amazon seriously. A year ago, this wasn’t the case and we saw many developers just go for deals with Amazon for cheap or free distribution.

Now that Amazon has a footprint and may even eventually get into smartphones, they’re now a must-have for serious Android developers.