Drawbacks in the 3 tier architecture...

Dear all,
If anyone knows about the drawbacks and the limitations of the 3 tier architecture, pls let me know. I'm doing a project on "A new architecture for web applications scalability". For this I'll be mainly concentrating on the 3 tier architecture and tryng to come up with solutions for the problems a 3 tier architecture has when it comes to web applications scalability, maintainability and availability.


My mail address is [email protected].

Thank you
Erangi..