Creating an Azure virtual machine availability set, properly configured for FTP service, is best done with an ARM template.
Configuring an Azure VM availability set to handle FTP uploads requires a little knowledge of how PASV mode works.
If you're going to call Azure Storage blobs from AJAX, you may need to set Cross Origin Resource Sharing rules on your account.
To serve blobs directly from Azure via HTTP, set your container permissions and MIME types properly.
When removing a defunct user account, the safe move is to delete and merge; alternately, you can just obfuscate the account's email and password.
The LinqToTwitter library relies on asynchronous methods to do its work; here's how to get them to work with synchronous programs.
This tutorial describes tweeting with media (pictures) in .NET via the Twitter REST API, using the LinqToTwitter library.
This tutorial / walkthrough describes installing LinqToTwitter into a Visual Studio .NET project and using it to make plain-text tweets.