(CNN) -- It's no longer the era of the BlackBerry -- or the iPhone. According to a market research report released this week, Google's Android operating system now is the most popular smartphone platform in the United States.
The first phone running Android, the T-Mobile G1, wasn't announced until September 2008. Only 2½ years later, the research firm comScore says Android is No. 1 in the U.S. with 31.2% of the market, compared with 30.4% for BlackBerry's business-friendly operating system and 24.7% for the iOS from Apple, which powers the seemingly omnipresent iPhone.
What accounts for this meteoric rise? Here's a summary of what makes Android popular, based on conversations with smartphone experts, buzz on the tech blogs and reader responses to our query posted on the @cnntech Twitter feed.
Consumers like choices
There's basically one iPhone.
There are dozens of Android options.
At last count, in January, there were 74 smartphones for sale running Google's operating system, said Mark Donovan, a senior analyst at comScore. A Google spokesman said there are 170 Android devices in total.
Among phones, Android has models on every major U.S. wireless network and on some of the smaller carriers that offer prepaid plans. AT&T was the exclusive iPhone carrier until recently, when a Verizon iPhone 4 was released.
Then there's price. Android offers choices here, too. Some Android phones cost a few hundred dollars. Others are free with a contract.
All of these options make for a sometimes-inconsistent Android experience, Donovan said. But it also means consumers can pick exactly what they want instead of going with the one-iPhone-fits-all approach.
On Twitter, a user named zwackone wrote, "Choices, people want choices --Android offers variety and freedom of choice."
Wired explained it this way in 2008: "Apple's device was an end in itself -- a self-contained, jewel-like masterpiece locked in a sleek protective shell. Android was a means, a seed intended to grow an entire new wireless family tree."
Integration with the internet
Google kind of rules the internet. The company's prominence in search, online mapping and voice-recognition technology put it in a good position to tackle the smartphone market, said Mike Gikas, an editor at Consumer Reports.
Google's Android operating system integrates with "the cloud," allowing users to sync their Google, Facebook, Twitter and phone contacts easily.
That's been a big hit with consumers who are looking for some simplicity in their lives, Gikas said. And Google's GPS driving directions app -- available free on Android phones -- is another big hit.
Openness of the Android Market
Saying something is "open" in the tech world is getting to be about as stale as saying "LOL." But Google's app store, the Android Market, sets itself apart from competitors in that anyone can post an app -- and those apps are allowed to do to a phone just about anything developers can dream up.
By contrast, Apple approves applications for the iPhone before it will make them available. Google takes an anything-goes approach, pulling apps that don't comply with its policies but not filtering them in advance.
"The three of us all believed that it was too difficult to get new products out to consumers in a timely fashion," Android co-founder Nick Sears says in a promotional video. "And we thought the missing link was not having an open platform. And that's how Android got started."
Kingfysher, another @cnntech Twitter follower, put it like this: "Flexibility and freedom. Apple's icy grip is restrictive."
Apps that do what you need, not what you don't
In terms of app numbers, Android is losing big to Apple.
Google's Android Market has 150,000 apps. Apple has more than 350,000.
But Gikas said the Android apps pretty much cover everything an average consumer would want a phone to do, so having more apps isn't necessarily the best selling point.
"Are you going to have 15 beer mug drinking apps or those obnoxious noise-making apps that do human bodily functions? No," he said of the Android operating system. "But you're going to get everything you need."
He added: "You can get Angry Birds on Android. You're not going to miss out."
Donovan said Apple is still winning the apps race.
Stealing the best of everything and then giving it away
Google doesn't charge for its mobile operating system, which is another reason carriers and handset makers would choose to go with it, analysts said.
But there's another factor, Gikas said. Google watched the smartphone market develop a bit and then appropriated the best ideas, he said.
Example: multitasking, which Gikas said was developed by Palm but has become known as an Android feature.
Now, Android finds itself leading the market with certain functions. Its phones are pushing forward with larger screens, integrated contact systems, more customization and access to faster wireless data networks, he said.