Several of the acronyms you list are general Internet or chat related "words."

IIRC = If I Recall/Remember Correctly
TAFN = That's All For Now
.bomb = generally refers to the the ".com" bust in the late 1990s when many of the high flying .com investments in companies that were great ideas but with no real business model for revenue went bust/folded.

As for air fare class codes, some of them will be listed in the FlyerTalk Glossary, which is located at the top of the page on the far right under the "Help" menu. Click on Glossary and this page will come up:
http://www.flyertalk.com/glossary/

If there are any specific air fare class codes, there are many members who would gladly assist you in defining those, though they do vary by airline so try and be specific since the rules vary.

Hope this helps and let any of us know how we can help.

As for the acronyms - heck, I'm learning all that from my nieces and their constant text messaging!