Jakob Nielsen's site is always an interesting read as usability is one of my big obsessions.
It sounds obvious stuff really - if your site loads quickly and is easy to use - folk will not click away elsewhere, yet so many sites get this wrong. Horribly so. I have a huge problem with some blogging sites in this regard. And don't get me started on
Nielsen writes about a new survey comparing key performance indicators before and after a site usability overhaul - the average improvement was 83%. This is a smaller figure than a similar survey a few years ago but you'd expect that - surely we're all trying
to make better web sites these days. Hopefully gone for good are the days of waiting hours for a page to load just for it to say "welcome - click to enter".
Typical indicators are conversion rates (lead generation or sales), page view numbers and user performance - such as the time needed to perform key tasks. Interestingly you don't have to double your visitors to double your business - you just need to up
the conversion rate, which is a much cheaper proposition.
He says "spend 10% to gain 83%" - which is something any business should pay attention to.
Read more at useit.com