Whenever I am on the StackOverflow page, if a new answer shows up on a question I've posted the banner at the top automatically shows informing me of this. What was used to create this effect? I'm wanting to do something similar on a project I am doing as it would be very handy.
Welp, as is required in the "I'm building a web site" question:
You should totally use jQuery.
SO is built on ASP.NET MVC as its backend, as an FYI.