Instagram – Apple’s App of Year 2011 – has hit 27 million registered users bar, despite being available only on iOS platform. However, Intagram is hitting Google Play Store (formally known as Android Market) very soon. What makes Instagram so popular?

Instagram is a photo sharing app that applies digital filter effects on photos and uploads them to different social networking sites like Facebook and Twitter. The big deal is Intagram is that it is free and easy to use. The reason behind Instagram’s success is casual. Everyone wants to look good in photos, especially if those are to be uploaded as Profile picture or Facebook cover to show off to friends. And Instagram does all editing, enhancement and uploading, making it very user-friendly and everybody’s favorite.

Instagram made debut in Apple App Store in October 2010. By the end of 2010, Instagram reached one million users milestone. After six months in June 2011, Instagram announced that it has five million registered users and 100 million photos were uploaded through Instagram by that time. Instagram surpassed 10 million users in September last year. In November last year, the 13 month old app had 13 million registered users. Realizing the popularity of the photo-sharing app, Apple crowned Instagram as App of the Year 2011. Surprisingly, it became more and more popular afterwards by hitting 14 million downloads in past 5 months.

With recent fund raising, the photo-sharing app maker is believed to be worth $500 million.

According to an estimate, about 700,000 android devices are activated everyday and we are living in an era of social networks where Facebook, as a major social platform, has 845 million active users.

Meanwhile, Instagram has announced its Android-based app is likely to hit Android devices really soon. Even, there are backstage talks that the app has been developed. We cannot imagine how popular can Instagram get after being released on the Android platform.

After releasing the Android app, WP7 app is also being expected.

(reported by Johnny Wills, edited by Surojit Chatterjee)