Site Hangs Waiting for External Javascript
This applies to you if you use Google Analytics, or any other third part javascript and your site stops responding whenever the third party site goes down.
One of the main ways this affects users is the page does not display in their browser, and in the lower left of the browser window they see ‘Transfering data from pagead2.googlesyndication.com’
The problem is caused by the script tag being in the <head> section of your site. If you move it to just before the </body> the browser will render your entire page before waiting for the third party site to respond. This will also improve the overall responsiveness of your site.