Andrew King has a new post up highlighting recent research on how long people will wait for a page to load. Previously, the magic number was 10 seconds, but broadband has decreased our patience for slow sites.
A JupiterResearch survey found that 33% of broadband shoppers are unwilling to wait more than four seconds for a web page to load, whereas 43% of narrowband users will not wait more than six seconds (Akamai 2006).
Google found that moving from a 10-result page loading in 0.4 seconds to a 30-result page loading in 0.9 seconds decreased traffic and ad revenues by 20% (Linden 2006).
Plus a very real impact on sales:
Tests at Amazon revealed similar results: every 100 ms increase in load time of Amazon.com decreased sales by 1% (Kohavi and Longbotham 2007).
WordPress 2.5 no longer provides an option to turn on gzip compression. According to Matt Freedman, the “option was axed for the reason that it’s better to enable compression on the server, rather than through WordPress.”
This is probably true because the option was turning on php compression instead of setting it in apache. However, it was still a surprise to realize my site was no longer being compressed.
To remedy the problem, I added the following to my .htaccess file in the root directory:
Header append Vary Accept-Encoding
This is the code for Apache 2.0 as suggested by Ryan Williams. Similar code for Apache 1.3 can be found.
The main point is the if you used to rely on WordPress 2.5’s gzip option, you’re going to need to find an alternate solution.