Interesting article on aWeber's blog.
Popover forms are inline forms that pop in a web page (thus avoiding pop-up blockers). A lot of people use them to request sign-ups for e-mail lists, and in this article, over a couple of tests, looks like they got better results with faster times.
I would have thought that longer times would help the user get interested on what you say. (I guess that depends on if they are more interested AFTER reading your content or BEFORE…)
Of course, given the anecdotal nature of the data, it is probably best to run your own split tests for this.
