"It appears that several people are suffering today from what is known as the Spinning Issue. This is where the Editor does not finish loading and you get a Spinning icon in the middle of the post.
If this is affecting you please answer ALL the questions below.
1) What Browser and version are you using? (Normally Help, About will tell you) Make sure you have the latest version
2) Do you have any Popup/Ad Blockers installed?
3) Have you tried clearing your cache (http://www.wikihow.com/Clear-Your-Browser's-Cache)
4) Do you have the latest version of Adobe Flash (http://get.adobe.com/flashplayer/?promoid=BUIGP)
5) Does it happen if you use another browser like Chrome?
6)Have you tried using the other editor either New/Old. (To revert back to the Old/New editor go to your Dashboard and click on Settings and then scroll down to the bottom of the page and select the Old/New editor)
7) If you use IE8 or IE9 try pressing the compatibility button (at the end of the address bar) when you're on your blog page.
8) What is your Blog URL/LINK
9) What Operating System are you using? (eg Windows 7, Vista, XP, Linus, MAC)
10) Try resetting your Modem/Router.
11) When did the problem first start happening and have you recently made any software upgrades that coincide with the issue.
Google Engineering are now aware of this issue and any updates will be communicated in this thread."