but I have one problem, I make two or more requests after every two mins, one for getting new questions posted on stackoverflow, another for get answers and comments of questions timeline by a specific user and one more for getting the reputation of specific user. how should I handle them then?

Ah! good, I was already polling 1 request after every 2 mins. means its okay. :) thanks.

oh really it is You.....! wow great. I sometimes wonder that how people create one thing for usage when it is not available in the core. like Silverlight does not provide anything for gzip decompression but you did. (Y) :)

but you know, WebRequest.RegisterPrefix did not help me, I had to use Silverlight.SharpZipLib library for decoding gzip content. still many many thanks to you. :)