UPDATE 15 December 2020: a lot has changed since this original post from March 2011! and Page Speed Online is no more. If you’re serious about page speed, here’s a few good places to start:
Original article below:
Website loading times are important for conversions and in recent times, another important factor in Google’s ranking algorithm.
So it makes sense that webmasters concerned with rankings (most of you I’m sure!) would be focusing on this. Matt Cutts even went into some detail about this in a video not long ago.
There’s a lot you can do like minifying JS and CSS files (this means you, Magento!) and using CSS sprites and images that have been better optimised.
But Google, as helpful as ever has released Page Speed Online – a new tool to help analyse page loading times along with providing recommendations. It’s so smart, it even helps with mobile versions of websites (which are quite different to regular versions).
I just ran it for a few websites and it’s been very insightful and proving to be invaluable in our pursuit for better rankings!