CD's or CDs ?

Obviously you wouldn't write "compact disc's" but I would contend that historical rules of grammar do not apply to abbreviations. In earlier and simpler times people did not have a multiplicity of two-letter acronyms to deal with, and thus the question did not arise.

Nowadays, in the high-tech environment, we hawe have to contend with not only with CD's, but PM's and IM's, all of which look much more natural in the plural when embellished with an apostrophe.

So, for my part, while I am well aware of the arguments to the contrary, I will continue to write "CD's," while continuing to be just as pedantic as before whenever I see "it's" when it should be "its".

Murray