Stoyan Stefanov of the Facebook engineering team shares that the updated Like box is 2-4x faster and is considerably lighter than the previous version. The Facebook Like plugin now loads in 0.5 seconds, as opposed to 2.3 seconds and while the previous version was 245KB in size, it now weighs a mere 46KB.
Facebook improved the performance of the plugin by switching to inline CSS styles (as opposed to using external stylesheets) and by squeezing multiple scripts into one – the plugin thus has to make fewer web requests.
How do you get the faster Facebook Like box for your website? First, does the Facebook embed code on your website look anything like this?
XFBML version (old)
<script src="http://connect.facebook.net/en_US/all.js#xfbml=1"></script> <fb:fan stream="false" name="PAGE_NAME"></fb:fan>
IFRAME version (old):
If your embed codes are different, you are covered as Facebook will automatically serve you the improved Like box. Else, you are using the older /deprecated version of the Facebook Like box so head over to developers.facebook.com and generate the new embed codes.