Japanese gets really creative with those. It has both Japanese -made English (wasei eigo) with proper acronyms, and interesting Japanese ones where acronyms often don't quite work like in English.
Some examples:
SNS: Social Networking Service (Social Media)
Furorida/Florida: "Furo Ridatsu", basically "bath AFK" for "I'm offline for a moment to take a bath".
草 (kusa, grass): The Japanese word for laughter is "warai", so people started typing "wwwwww" to show laughter. And because that kinda looks like grass, 草 came to mean "lol". I recently saw someone explain "rofl" in Japenglish as "big kusa".
Ichaipu - mix of Icha(flirty) and Sukaipu (Skype), i.e. flirting in an online call