If you have hardcopy of the June 2006 FastCompany magazine, page 42 is about how picturephones introduced in 1964 never made it big (although iChat might change that :) Here's a quote from the director of customer research at AT&T Labs:
Around 1971, I surveyed 173 executives in the Chicago area ... The bottom line was, there were virtually no business situations for which the picturephone was best.
To read the article online, you can enter the access code found on page 10 of the June hardcopy issue, or wait until next month and read it in the free archives.
