OWA

Hi.
I enjoyed reading Scott Lape’s article about OWA. Had a couple of questions
about that topic.
1. How many clients can be simultaneously processed in an efficient manner
by one computer that has only OWA and IIS installed on it (not MS Exchange
Server)?
2. Concerning basic (clear text) over SSL authentication. What type of encryption is SSL based upon?
3. Regarding Windows NT Challenge and Response (NTLM). What type of
encryption is used for it?

Thank you.