Question: I received a new iPhone yesterday and connected it to my home Wifi network.

On content heavy sites it runs perfectly fine, but if I use either the Youtube site or the Youtube app I can't watch anything. It takes forever to watch 5 seconds of video.

My first question is, how can I be sure that my phone is using local Wifi for the internet connection and Youtube app (it says connected in the settings, but is there an icon in the display etc. to confirm Wifi connection)?

Any suggestions as to why Youtube runs slow when other heavy sites load without problem?

Answer: 
[OS X: Install and Run Firefox 3 and Firefox 4 on the Same Computer | Mozilla Firefox | Tech-Recipes](http://www.tech-recipes.com/rx/2828/os_x_install_firefox_2_firefox_3_same_computer/)

Or just make copies of `~/Library/Preferences/org.mozilla.firefox.plist` and `~/Library/Application Support/Firefox/`.
Once you install it in separate directories, you can in fact **run them both simultaneously**. 

It just takes a little Firefox flags magic as explained here in [this article](http://www.shankrila.com/firefox/howto-run-firefox4-firefox3-simultaneously/).