After taking my YUN home and configuring for my home network, I was finally able to allow YUN to go wireless! Then, I realized that my Arduino code needed two separate HTTP Clients from the HttpClient library — one for when the button was pressed, and one to check the state of the button. After fixing that, the button responded correctly!
The next step was putting my code online. As I learned earlier, I needed to use a service that would keep my code running, unlike a typical file upload to my GoDaddy web server. I looked into Heroku and Nodejitsu. I ended up going with Nodejitsu because the beginners instructions were so clear.
I followed the instructions, and put my code at http://button.nodejitsu.com
Then Voila! The button works!!!!!