Only for very formal events. It's very nice, but too much for most occassions. Good if you want to get noticed, but some people may make fun of it rather than appreciate. . . Depends on your age and the maturity of your contemporaries.
So to answer your question, these are Fascinators, they come as pins, sticks, and headbands. Probably the most famous wearer right now is Kate Middleton. Since she will be princess/queen, I'm sure they will catch on. Usually weddings & formal events