I even noticed a comment above that said Bottle looks just like Itty. Yet because I brought up the Ruby framework that Itty is essentially a port of, I'm getting down-voted like crazy. I will never understand why Python people dislike Ruby so much, and vice versa.
Python people don't dislike Ruby, they dislike the Ruby community's habit of assuming that Ruby somehow did it first and did it better. :3
Decorators, a Python 2.5 feature, weren't around when web.py was first released, so they couldn't have been used initially. Even after Python 2.5 came out, it took some time for decorators to be widely embraced. But routing and other kinds of dispatching (e.g. adapters and multimethods) are an obvious and indeed commonplace use of them.
I didn't down-vote you. I did get ever so slightly annoyed with your implication that Sinatra was the first to do this kind of thing and therefore necessarily a source of influence. Neither half of this claim is correct. Sinatra wasn't the first. Even if it were, it need not have been an influence; I wouldn't claim that web.py had to have influenced Sinatra just because it preceded it.