Hi,
in this article "How To: Use Impersonation and Delegation in ASP.NET 2.0", http://msdn.microsoft.com/en-us/library/ms998351.aspx
under Disadvantages for Impersonation, it says this:
Scalability. The impersonation / delegation model does not allow you to make efficient use of database connection pooling because database access is performed by using connections that are tied to the individual security contexts of the original callers. This significantly limits the application's ability to scale to large numbers of users.
While it would be hard for anyone to give an exact number of users that this is appropriate for, in everyone's experience, how many users is too many for this type of database access? I'm sure there are variables: the types of database operations and size of datasets returned, Network bandwidth, procs/ram/drives used& ...
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