Karl Groves said:
To expand on this a little:
We recently ran a usability test on a large non-profit's site where, for
some unknown reason, they chose to create some text in blue, with
underlines. The main body text was normal black-on-white text, but there'd
be some parts where a word or phrase was marked up as blue & underlined.
It was very weird, as if someone in upper management created a mockup to
indicate where they wanted a link but the "developers" just left it that
way.
At any rate, ALL participants were confused by this, attempted to click the
words, and got frustrated when clicking did nothing.
While this was an extreme case (by being both a different text color AND
underlined), my experience tells me that people exhibit the same behavior
whenever ANY text is underlined.
-Karl