The previously optional Facebook Messenger app has now become a mandatory part of the social network's mobile experience in order to keep using the mobile chat function. But what made it more controversial is the app's supposed invasion of privacy as presented on a Huffington Post article released last December 2013.

According to the blog, Facebook Messenger's Terms of Service agreement include the following:

"Allows the app to change the state of network connectivity Allows the app to call phone numbers without your intervention.This may result in unexpected charges or calls. Malicious apps may cost you money by making calls without your confirmation. "

"Allows the app to send SMS messages. This may result in unexpected charges. Malicious apps may cost you money by sending messages without your confirmation. Allows the app to record audio with microphone. This permission allows the app to record audio at any time without your confirmation."

"Allows the app to take pictures and videos with the camera. This permission allows the app to use the camera at any time without your confirmation."

"Allows the app to read you phone's call log, including data about incoming and outgoing calls. This permission allows apps to save your call log data, and malicious apps may share call log data without your knowledge.

"Allows the app to read data about your contacts stored on your phone, including the frequency with which you've called, emailed, or communicated in other ways with specific individuals. "

"Allows the app to read personal profile information stored on your device, such as your name and contact information. This means the app can identify you and may send your profile information to others. "

"Allows the app to access the phone features of the device. This permission allows the app to determine the phone number and device IDs, whether a call is active, and the remote number connected by a call. Allows the app to get a list of accounts known by the phone. This may include any accounts created by applications you have installed."

A lot of users, of course, were threatened by these terms. But Facebook made a quick comeback saying that all concerns regarding its app are based on wrong information. With this, the developer clarified that those quotations in the Huffington Post are outdated.

If you're an Android user, you might ask "Why is the Messenger app requesting permission to access features on my Android device?"

Don't worry, you're not in for a trouble as Facebook explains that they are just doing this because Google recently tweaked the language it uses in its Android app permissions:

"If you install the Messenger app, you should see a screen letting you know that the app is asking for your permission to access information or use features from your Android phone or tablet. Almost all apps need certain permissions to run on Android, and we use these permissions to run features in the app. Keep in mind that Android controls the way the permissions are named, and the way they're named doesn't necessarily reflect the way the Messenger app and other apps use them."

Despite this clarification, we cannot also deny the fact that the iPhone version of the app offers a more secure approach, for users have the option to decline to give permission to the app for some features like access to the address book and microphone without compromising the chat function.

Competing with popular messaging apps like Viber, WeChat, Kakao Talk, Line, and Snapchat, Facebook Messenger also offers interactive features like photo sharing, group messages, video call, stickers, and audio clips.

Zuckerberg didn't go into details when it comes to monetizing the app, but the CEO guaranteed that they will not be taking "cheap and easy approach and just try to put ads in." "The payments piece will be a part of what will help drive the overall success and help people share with each other and interact with businesses," he added.

Now, Facebook is clearly eyeing on strengthening its messaging services as Messenger runs alongside WhatsApp which was acquired by the company early this year.

How do you feel about the mandatory shift to Facebook Messenger app and its privacy options? Sound off in the comments section below!