If you Google the term Mubby and hit the I'm Feeling Lucky button it brings you here: http://www.mubbybooks.com/.
Here is the description according to the website:
Mubby Books: Publisher of Gifted Youth of America Mubby Books publishes the works of gifted youth, primarily ages 18 and younger. This population of gifted youth is potentially quite great and may lie quietly undiscovered...until someone recognizes and encourages the exploration, unfolding, and development of these gifts. I believed. And that’s how Mubby Books started. Lucy Campos Publisher and Founder of Mubby Books
I think it means something in Russian as well because there is a Russian site for mubb shoes. I think I need to buy a pair just to have them.
However, this was a name given to me about 14 years ago by this young man:
Pa is on the left, Johnny , and Ama
He was laying on the bathroom floor getting ready to get in the tub, his mom looked at him and said "Johnny, can you say Aunt Kris?" He looked up and said "Mubb." The same thing occurred about 6 months later verbatim. So I became Mubby...I like it because I know there aren't many of us out there (I tried to find more). Though, I do not like that my sister's boys now call me Miss Mubby. They need to drop the Miss thing, it's way too formal. I use this name for all of my log-ins on all of the sites to which I belong, usually it is not an issue getting this name, but sometimes I add the year that he was born...96 if the user id needs to be longer.
My family is a little odd, we like to stop at signs that have our names (first, middle or last) and have our picture taken (I don't have any on this computer at the moment, shocking I know, or that would have been included too). This is not something that I will ever have to worry about with the term mubby because, alas, it is not a real word. It does make me feel good that even as a teenager, he still calls me this every time he sees me and now I have 4 other little ones that call me this as well!