It's more like the birhplace than a style. It can be traced back to, some say, Cybotron (Juan Atkins) with his release of "Alley's of Your Mind" in 1981 which is considered or disputed to be the first official techno track. Oddly if it was released today we would probably be called electro.
I was first introduced to Detroit Techno in 1987 through Rythmn is Rythmn (Juan Atkins, Kevin Saunderson, Derrick May) with a track called "Feel Surreal". The main difference to me between Detroit and techno from other locations is the funk. Detroit is the birhplace of Motown, and definetly can be heard in the techno. Listen to Carl Craig's "The Climax", and you'll know what I mean. Back in da day of warehouse parties (notorious for bringin house to Toronto) we used to play alot of Detroit Techno (The Dance, Wiggin', Frequency, Acid Storm).
In fact I actually despised most of the techno coming out of Europe in the early '90's (didn't have the soul), but in that changed as soon as labels like Soma and Mute started puttin' out some dope beats (Emmanual Top, Earl Brown, Equus).
Funky Techno comes from all over the world now, but I truly beleive it's birthplace is Detroit, and even Chicago via Green Velvet's Relief records (of course to him, everything is house). Even some of the stuff Larry Heard (Amnesia and Washing Machine) and Ron Trent (Altered States)put out is very influenced by Techno.
My 2 cents.
Peace,
Derek