Google Spreadsheet New(-ish) Column Sort Tool

Google announced a couple of new features for Google Docs a few weeks back. But, I only remembered about the new sort feature this evening :-). We've always been able to sort columns in Google Spreadsheet using the button tool. However, if you hover over the bar beneath a column label (frozen row 1), you will see a tool tip like the one shown above. This lets you choose ascending or descending sort and then perform the actual sort.

I use Google Docs daily and am constantly amazed how useful it is. I looked around Amazon and O'Reilly's website for a Google Docs book or booklet but couldn't find one. Anyone know of a Google Docs hints and tips site? Google's Google Docs What's New page is useful. But, I'm sure there is a lot more that I could get out of Google Docs if I had a good reference to read.

BTW: Here's another Google Docs tip. If you preface the URL with https:// instead of the usual http://, you can access the site securely using SSL (Secure Sockets Layer).