We used a Modal and some AJAX code to avoid one page reload due to a form submission. In the Notes application, as it stands, a similar technique could be used when creating a new note, editing existing notes, and deleting existing notes. In each case, we would use a Modal, some AJAX code to handle the form submission, and some jQuery code to update the page without causing a reload.

But wait, that's not all. Consider the sort of dynamic real-time user interface wizardry on the popular social networks. Imagine what events and/or AJAX calls are required.

When you click on an image in Twitter, it pops up, you guessed it, a Modal window to show a larger version of the image. The Twitter Compose new Tweet window is also a Modal window. Facebook uses many different Modal windows, such as when sharing a post, reporting a spam post, or while doing a lot of other things Facebook's designers deem to require a pop-up window.

Socket.IO, as we've seen, gives us a rich foundation of events passing between server and client that can build multiuser, multichannel communication experiences for your users.