Transportation on Facebook Messenger

Today they introduced nicknames[1], chat colors, and custom emojis (replaces the "like" button) on the mobile messenger apps (haven't checked web).

So my guess is that the Messenger guys just try to add whatever they think might be cool and then see if it works.

As for their goal... it's just so people spend more time on Messenger of course.

[1] If you are in a chat (1-on-1 or group) you can rename anyone with a nickname that will show up when they talk instead of their Facebook name.