It's based on a parallel universe in which there are technological advancements but it's powered by steam and whatever the Victorians would have used.
The whole look is Gothic Victorian in a Jules Verne kinda way and true snobs know that you can't just go around sticking gears from watches onto stuff and call it Steampunk, everything has to have a realistic reason for being on it.
Top hats seem to be a basic easy option for the steamypunker. "Hey look at me I'm Steampunk" ..... no, yer just a twat in a top hat and swimming goggles.
Lady Clankington has the right idea. She sells her Death ray vibrators so you can Steampunk yer hoo hoo .
While Steampunk is getting yet another resurgence of popularity Old Knudsen stopped wearing his Pith hat after the Boer war. I used to put the steam up the fuzzies, standing there alone facing hundreds of wogs with me broken rifle in one hand and me bayonet in the other, fighting for King and cuntry. Lucky they were still asleep in their huts and that I had a Gatling gun beside me. War is hell ..... if you face me and pretty good fun if you are me.
I don't think I'll be seeing any spides outside of the Belfast pubs puking into their Stovepipes anytime soon, though they would be handy for hiding a bottle of Buckfast under.
Lady Clankington is young, hot and shapely. She could wear anything and look good. No wonder Steampunk is popular with the nerd types. It's like buying clothes cos you saw how good they look on the models.
The reality of Steampunk if you aren't in LA or somewhere else that out-crosses is that it looks a little different than imagined but top marks for participating. If it's harmless, makes you happy and I gets to see tits then it's all good.
Of course some people have this natural talent of looking like a sex offender no matter how they are dressed.
Long hair and ponytails on a man is only acceptable in the jungle and under the age of 35, anything else then yer getting into creepy, grungy old man territory whose chat up line is,"You remind me of my daughter."