What is the probability distribution of a web-server receiving a client connection request? An internet search for the probability distribution of a server getting a connection yielded no relevant results.
My guess is it would be be poisson or normal distribution, but I need something a bit better than a guess, so please cite a source for your answer!
 A: This question is too broad to have one answer for all circumstances.
When looking at the number of requests as a function of number of websites, you are hiding a third latent variable, which is the website type.
There are websites that do not attract any kind of user engagement (e.g. "about us" pages)  and there are websites that attract a lot of user engagement (e.g. Facebook and cross-validate (: )
The Poisson distribution assumes a memory-less behavior, this could be a good model if each web request for the website is single, and independent of each-other.
For example, I would expect that the wallmart's opening hours page would have this behavior.
But looking at an eCommerce websites (e.g. eBay, Amazon) , the behavior is much more complex, just imagine how does a black Friday would affects the number of requests.
In addition I would expect to see an underlying distribution of user types, for example "bargain seekers","compulsive buyers","feedback oriented" that would generate the observed "request distribution" in question.
To sum up, I doubt that you would find a "silver bullet" distribution for all website's request count. There are a lot of factors that depend on the website type and the user it attracts that need to be accounted for
