The invitation to an April 4 event suggests Facebook could be set to reveal its own mobile operating system built around the social media network's features and services.

Rumors of a dedicated smartphone have been circulating around Facebook for over a year, but its CEO, Mark Zuckerberg, recently dismissed them by emphasizing the company's true aim -- to be on ALL smartphones.

And while a dedicated handset might only chime with the most dedicated Facebook user, an operating system with the social network and its features and services at its core, is another proposition entirely.

Countless surveys and studies have revealed over the course of 2012 that interacting with social media, and in particular Facebook, is the most popular online activity.

According to Nielsen, Facebook is currently the most popular internet destination in the US.

In July 2012 alone, US internet users spent a combined 121 billion minutes on Facebook, Twitter and Pinterest. In fact, 30 percent of all online time via mobile in the US is spent on social media sites.

A similar study by Pew Research, published in December found that the same is true in the UK where social media is the number-one internet destination, attracting 52 percent of the country's internet-using population.

Sources claim that the event on Thursday, the invitation to which simply reads: "Come see our new home on Android," will showcase a modified version of Android running on a HTC smartphone that integrates Facebook into its homescreen.

This rewriting wouldn't constitute a forked operating system, such as that used by Amazon on its Kindle devices, but more of a skin, like those used by all Android handset manufacturers, to differentiate their handsets from their competitors.

HTC has a track record for attempting to integrate greater Facebook functionality into its devices.

Its SoHo and Cha Cha smartphones both featured a dedicated Facebook button and every time rumors have resurfaced regarding a Facebook phone, HTC is named as the manufacturer.