proxy account /proxy user

HI ,
Can anyone explain me the real use of proxy account /proxy user? I have gone through different sites and books but still I am in confusion.
Please confirm me the below points:

  1. Is it necessary to create Proxy Account? Without Proxy Account we will not continue the working process? (Working with BC connecter, workflow, EP etc.)

  2. It is possible to create only on server? Not on client?

  3. Is it mandatory to create even Development server?

  4. What is the difference between normal account BC account

Best Regards,
KIK

Yes it is mandatory.

i did understand - can you explain it

If you are using the above application such as EP frame work , workflow in the development server- then you need to create it.

THIS IS USED FOR COMMUNICATION BETWEEN THE AOS AND APPLOICATIONS SUCH AS ROLE CENTERS AND EP FRAMEWORK,

WORK FLOW AND AIF WEB SERVICE. BEFORE INSTALLING THESE THINGS PROXY ACCOUNT MUST BE CONFIGURED IN THE SYSTEM.