(This page also in Dutch / Nederlands)

Usability is the measure of something that can be used. That 'something' can be a screwdriver, a bottle, but also a web site.

The only way you can tell how good a site is to use is by observing visitors to your website and noting where they stumble. Abeleto uses the collective wisdom gathered through such observations to tell you what can be done to improve the usability of your website, and applies this wisdom in building websites.

About usability:
Column of web usability expert Jacob Nielsen