Usability is a term used to denote the ease with which people can employ a particular tool or other human-made object in order to achieve a particular goal.
human brain has some limits on its capacity for processing information. Argument for limiting the number of options in navigation menus;
user shouldn't need to wait more than 2 seconds for certain types of system response;
users stop using the site if they aren't able to find the information or access the site feature within 3 mouse clicks;
80% of the effects comes from 20% of the causes ("80% of your sales comes from 20% of your clients");
predicts the time required to rapidly move to a target area, as a function of the distance to the target and the size of the target;
the summary of the article is presented in the beginning of the article;
Web users don't prefer optimal ways to find the information they're looking for. Instead they permanently scan for quick'n'dirty-solutions which are "good enough";
the tendency for visitors to stick to the first design they learn and judge other designs by their similarity to that first design;
Web users tend to ignore everything that looks like advertisement. they focus only on the parts of the page where they would assume the relevant information could be, i.e. small text and hyperlinks.
Eye tracking is the process of measuring either the point of gaze ("where we are looking") or the motion of an eye relative to the head.
Heatmaps from eyetracking studies: The areas where users looked the most are colored red; the yellow areas indicate fewer views, followed by the least-viewed blue areas. Gray areas didn't attract any fixations;
(Zeigarnik-Effect): based upon the fact that human beings can't stand uncertainty (movies, articles with an abrupt ending, often leaving with a sudden shock revelation or difficult situation). This often tend to force them to read the ad, click on the banner or follow a link;
things that are connected to our personal concept are remembered better than those which aren't directly connected to us;
transforms block-shaped text into cascading patterns that help readers identify grammatical structure. [Live Ink]
Visualize Information - Representing information in spatial or visual relationships can make complex data sets clear and understandable: