It’s hard to argue that 2009 wasn’t the year of Twitter. Yes, the questions about monetization loomed over the young web company as soon as it started gaining popularity, and they’re still largely unanswered. But people loved this new way of communicating via 140 character messages that go out to everyone who wants to hear them. So much so, that everything else (even money) wasn’t very important.

So what  made Twitter?

1. Users

Many theories were spun about Twitter’s user base. Some said that teens aren’t using the service.Some said that’s not true. Much hubbub was made of the fact that many who signed up for Twitterdon’t actively use the service.

But there are two things about Twitter users that largely contributed to its stellar rise in popularity. First, it’s used by regular folks, not just tech-savvy geeks. And second, it’s become the favorite service of TV, movie and music personalities. The most popular guy on Twitter is not Twitter’s founder — it’sAshton Kutcher. After him comes Britney Spears, Ellen DeGeneres, Barack Obama, and Oprah Winfrey. When all these people are into something, you can bet that thousands will follow.

2. Reach

Furthermore, Twitter became a great way to run charity eventsbreak news, promote your work and connect with your fans. Events like Michael Jackson’s death were followed on Twitter first, and major media outlets second, simply because Twitter’s tiny chunks of information travel faster than professionally written news stories. And when the Iran election results started a wave of riots across the country and protests worldwide, Twitter was the glue that held bits and pieces of the story together.

3. Great New Features

On the development side of things, 2009 was an immensely important year for Twitter. The notoriously feature-shy service was largely turned into what it is today by its users. Originally, features such as retweets and hashtags were forged by the user base, not the developers. Furthermore, third-party clients such as TweetDeck and Seesmic raced to add the features that Twitter itself was lacking.

In late 2009, the folks behind Twitter decided to take a more active role in the shaping of the service by adding several important features, most notably Lists and built-in Retweets.

4. Real Time MAGIC

The momentum, however, was too strong. Real-time search — and Google’sGoogle inability to best Twitter at it — became a huge trend in 2009. Everyone wanted a piece of it, and Twitter had the goods. When you want to find out what’s happening right now, this very minute, Twitter’s search trumped Google, and Google had no choice but to react. Luckily for Twitter, the reaction came right on time. Both BingBing and Google signed a deal with Twitter to incorporate real-time results from Twitter into web searches, just as Twitter’s flat traffic figures became impossible to hide. The effect of this deal is still unknown, but when Google sends you traffic, you can bet it’s going to be noticeable.