Is it safe to assume that when a user requests an .aspx page via HTTP, that ASP.NET creates at least 1 thread for it?
If so, how long does it last?
If 1000 people make the HTTP request to the same .aspx page, is there some recycling of threads involved, so it doesn't spawn different 1000 threads?
Each request is allocated a thread from the iis page pool. the idea is that this should be a short running process so that thread can be returned to the page pool for use by another request coming (page pool sizes are not huge, usually, like 50). So, if you have a long running request, it's important you make an async call to free the thread for some other request. then, on your long running requests completion, you will get another thread from the pool and finish up.
Bottom line, if 1000 people make requests at the same time and none of them finish, 50 or so will run and the other 950 will wait.