i bought a pair of "emu" boots 2 days ago that are like "Ugg"s and wondered "what's the difference??"...there pretty much is none besides the brand and the fact that the "Ugg" brand was trademarked shadily...UGG boots are generic for Australian sheep skin boots. boooo Deckers Corp:

"In Australia, and many other countries as well, Ugg boots (also spelt ug and ugh) are a style of boots that has been used generically for well over a hundred years. In 1984, an Australian formed an USA based company and managed to trademark this generic term.
[...]Deckers Outdoor Corporation and their subsidiary, UGG Holdings Inc. have been threatening legal action against companies that continue to use the generic words to describe the Australian icon, ugg boots
[...]Westhaven Industries, a non-profit organization, which employs 65 intellectually disabled people to make ugg boots at its factory in Dubbo, Australia, have also been threatened with legal action. "We have been selling sheepskin products for 30 years, long before ugg boots became trendy in America, and to have to give up the name is just ridiculous," Mr. Sullivan, production manager, said."It's like registering the name sneakers – it's a generic term that everyone uses.""
click the link above to read more... also saveouraussieicon.com