Where are these poll requests from SignalR coming from?

This is coming from the browser link feature in Visual Studio 2013 in the Standard toolbar. It is code that allows Visual Studio to interact with browsers running the code, and should only show up when running it in debug mode.

To disable it (until the fix to the issue is made live in an upcoming update), follow the directions in #4 of the msdn page to disable it:

1. Uncheck “Enable Browser Link” in the Browser Link menu item
2. Set appSetting “vs:EnableBrowserLink” to “false” in web.config or debug=false.

Or you can just ignore it. It wont do any harm, will only happen locally, and should be fixed soon.

Also see this question and this question.