Mozilla has introduced WebRTC based Firefox Hello feature, codenamed loop in Dec 2014, this feature lets you share page you’re browsing with others and also allows to do video chatting without the need of an account or extra plugins. The company has recently turned Hello into a system add-on and all of a sudden without mentioning the reason, a decision has been taken to remove Hello from Firefox 49.
Check this bug 128787 for more details.
We miss you Firefox Hello
Mozilla decides to remove Firefox Hello
The deadline has been set to remove the feature by August 1st, so that there is no need for the Firefox team to prepare and show Hello removal warning banner to Firefox 49 beta users. And the browser vendor is also taking steps to ensure not to deliver any updates for Hello system add-on in future versions of Firefox so that it doesn’t resurface.
Firefox Hello Alternatives
Here are the websites that use WebRTC, which might fill the gap of Firefox Hello.
Update: Mozilla has mentioned this in Firefox 49 release notes, and the link for the change points to Hello Status page.