Security Contexts in ASP.NET

If you, like me, were confused about the different security contexts in IIS and how can they affect the way that you connect to SQL server look no further, Keith Brown's article A tale of Three Security contexts in ASP.NET tells everything that you need to know. Just remember that in IIS6 things work slightly different (i.e. you now have application pools and the default ASPNET account has been replaced by the "Network Service" account).