This is the day and age of abbreviations, thanks to IMs and SMS. While academicians worry about its adverse effects on the English language, you should be worrying about its effects on your career.
It may be acceptable to type BTW, IIRC, FYI etc. in the virtual world, but it’s not looked kindly upon in the corporate world, and I am sure all of us have some time or the other made the mistake of using these abbreviations in our official emails.
Now you can of course choose to attend the email etiquette classes conducted by your organization or be smart about it and do what I do.
A simple AutoHotkey Script will fix this problem.
::BTW::By The Way
::IIRC::If I remember correctly
::FYI::For your information
To learn how to use these scripts, click here
Whenever you type these abbreviations, they will automatically get expanded, and in every application you use. Cool, right!
And the best part, you do not need to make a different script file for each abbreviation. You can just put all the abbreviation scripts in one and keep adding to them as and when you require. Just compile and run the file after each change.