I'm a loud-and-long applauder and a producer of bravos. (Especially with performers I've seen often and have come to feel that I "know.") I've never thought about it, abut I guess I do hope that my applause will be "infectious". It's fun, and I always assume that the dancers appreciate it.
Carbro, your post made me think of something. This season the Met did a series of live simulasts in movie theaters. These were in real-time, but also on a screen. Kind of like a hybrid: part live, part film.
In fact, in the old movie musicals, there are pauses after the big numbers, such as Fred and Ginger's dances, to allow the movie audience to applaud the dancing and not drown out the dialogue. Of course, there was no bowing in the films.
When movie audience responses petered out over the years (probably around the release of the "That's Entertainment" series? ), directors stopped including pauses, and studios began editing out the ones in older fiilms.
About 2/3s of the audience in the theater we attended acted as though it was a movie and showed no reaction during the times when action stopped so that the live audience in NYC could applaud. The rest of us applauded. I found myself so entranced by the idea that so many thousands of us around the world were experiencing a "live performance" at the same time that applauding seemed quite natural. Others, obviously, did not feel the same, even though just about everyone -- clappers and non-clapperst -- seemed to have been thrilled and moved by what we saw.
It was odd to be making noise in the midst of others who were sitting there, snacking on popcorn, immobile and soundless.