John Timmer over at ars technica reports that Fake popup study sadly confirms most users are idiots. Here's a taste:
Some researchers have tested how college students respond to fake dialog boxes in browser popup windows and found that the students are so anxious to get the dialog out of the way, they click right through obvious warning signs...
...Follow-up questions revealed that the students seemed to find any dialog box a distraction from their assigned task; nearly half said that all they cared about was getting rid of these dialogs. The results suggest that a familiarity with Windows dialogs have bred a degree of contempt and that users simply don't care what the boxes say anymore.
This is interesting, though not that unexpected. We know that when performing specific tasks on a website, users are focused on this to be point of not noticing or ignoring things that would normally be obvious.
There are two take-aways I can think of from this. Firstly if you need to present users with important information in the midst of a task, you'll need to go to great lengths to properly get their attention, and secondly that things like ads and 'promotional features' are unlikely to be noticed let alone comprehended when users are in this task mode.