Impact of performance

The major search engines measured how much web site slowdowns hurt their business metrics:

• Bing – A page that was 2 seconds slower resulted in a 4.3% drop in revenue/user.
• Google – A 400 millisecond delay caused a 0.59% drop in searches/user.
• Yahoo! – A 400 milliseconds slowdown resulted in a 5-9% drop in full-page traffic.

On the faster side, companies from a variety of vertical markets had praise for the benefits gained from improving performance:

• Shopzilla – Speeding up their site by 5 seconds increased the conversion rate 7-12%, doubled the number of sessions from search engine marketing, and cut the number of required servers in half.
• Mozilla – Shaving 2.2 seconds off their landing pages increased download conversions by 15.4%, which they estimate will result in 60 million more Firefox downloads per year.
• Netflix – Adopting a single optimization, gzip compression, resulted in a 13-25% speedup and cut their outbound network traffic by 50%.

Google, in their ongoing effort to make the Web faster, blogged that “we’ve decided to take site speed into account in our search rankings.” This is yet another way in which improving web performance will have a positive impact on the bottom line.

References:

• Steve Souders - Web Performance Optimization
• Cheat Sheet: Everything you wanted to know about web performance but were afraid to ask
• The Psychology of Web Performance