What do the shorted words mean!

[Sammx]

So I'm new to this, and have no idea what DD and SM and DS ect, mean! could someone help me out and explain with a list of different ones and what they mean please

[Lamentations]

Darling daughter, son, husband, partner, mother.

SM stepmother

[Lamentations]

And welcome!

[namechangedforthis1122]

www.mumsnet.com/info/acronyms

[namechangedforthis1122]

I had to keep referring to that when I joined

[TiptopJ]

When I first joined it didn't click with me that AIBU is an abbreviation. For at least a week I was reading it as eye-boo and wondering what the hell everyone was on about! Eye-boo to think?.Eye-boo to ask?
In my defense I'd just had a baby and was very sleep deprived