Security

<location path="upload" allowOverride="false">
  <system.webServer>
    <handlers accessPolicy="Read" />
  </system.webServer>
</location>

http://www.hanselman.com/blog/BackToBasicsWhenAllowingUserUploadsDontAllowUploadsToExecuteCode.aspx

Mobile Development

Xamarin.Forms
Sample App (https://github.com/xamarinhq/app-evolve)

Splash Screen (click)

Animated gif http://stackoverflow.com/questions/25808010/xamarin-forms-custom-loading-gif-as-activity-indicator

Android Custom renderer for tabbed page (forum)

xamarin-forms-tab-badge (GitHub)

Xamarin plugins (GitHub) 

Xamarin programmatically change page http://www.patridgedev.com/2015/03/07/xamarin-forms-switching-tabbedpage-tabs-programmatically/