Content Blindness

This happens in both the short and long terms.

Short term (reactive):

• On sequential pages (e.g., a sign-up form), if you have lots of very similar content, people will skim-read it at best—or just ignore it entirely.

Long term (habitual):

• People are used to the common advertising spaces on the internet (e.g., sidebar ads), and they'll pay less attention to it.