Import all contacts from Rediff, Yahoo, Facebook, Hotmail etc

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C#

Hello Sir,
Recently I am working on a project where I need to fetch all contacts of different email providers like Yahoo, Rediffmail, Facebook, Orkut, Twitter, Hotmail, LinkedIn, any Exchange Server etc. I have read this topic on all different forums. I did not found any relevent solution. Importing Gmail contacts I already know.
I feel I can get solution here on this forum. If you can not provide solution then what can be good approach of doing this. I think screen scraping in banned on lot of social networking websites.
I have read a lot about it. I have seen some forums provide solution in php and call it from asp.net. But isn't is possible by .NET alone. I need solution in C# classes or asp.net.

Any help would be appreciated.
With Regards,
Shyam Sunder Tinwar