....by the way... As in, BTW your English is excellent considering it is not your native language! I've also seen it used for ...back to work... and if I've learned anything from my daughter's text & instant messaging, it could mean about 50 other things depending on the people using it and their own interpretations.
Acronyms often puzzle a lot of people, especially of technical terms. A good way to find their meaning is to just google them.