Android’s market share grew 2.5% in the fourth quarter of 2011 to 47.3% of the smartphone market, according to data just released by comScore. In September Google’s operating system had 44.8% of the smartphone market. Smartphone users make up 40% of the overall mobile phone market.

Apple also grew in market share during the last quarter, and by nearly as much. In September Apple had 27.4% of the smartphone market. Apple’s market share grew 2.2%, hitting 29.6% in December.

Of course, with Apple and Android getting a collective surge of nearly five percentage points, someone has to have lost out. Well, perhaps unsurprisingly, the big loser appears to have been RIM. Their BlackBerry platform went into the quarter with a market share of 18.9%. By December they had lost 2.9% – more than either Apple or Android gained – to bottom out at 16%. Meanwhile, Microsoft and Symbian suffered smaller drops, finishing December at 4.7% and 1.4% market share, respectively.

ComScore also collected data about mobile phone OEMs (original equipment manufacturers). Apple gained 2.2 percentage points and ended December with a market share of 12.4% of all mobile phones, not just smartphones. That leaves Apple in fourth place, after Samsung, LG, and Motorola. RIM maintained its fifth place position. Of the top five mobile phone manufacturers, Apple was the only OEM to actually gain market share during the September-December period. Samsung held steady at 25.3%, while LG, Motorola, and RIM all lost market share.

Finally, comScore looked at mobile content usage (i.e., activities other than making phone calls) across all mobile subscribers, not just smartphone users. The most popular activity by far is texting, with 74.3% of users saying they had used their phone to send text messages. The second most popular activity at 47.6% was downloading mobile apps, followed very closely by using their phone’s browser at 47.5%. Just over two thirds – 35.3% said they used their phone to access social networking sites or blogs, while 31.4% played games and 23.8% listened to music. All of these activities gained in popularity in December. Downloading apps saw the biggest jump in popularity at just over 5%.

[via comScore]