Mark Walsh wrote today that "a panel of online advertising and media executives agreed that shorter is better. Given the short attention span of the Internet audience, pre-roll video ads generally shouldn't last more than 15 seconds."

Excuse me Mark (or panel that Mark is quoting), 5-seconds is more like it. I seem to recall a study done at Microsoft that measured user annoyance with video ads. They are patient for about 5.5 seconds until annoyance shoots UP.

Where is that graph again. OK, I just found it.

One conclusion that I do agree with is this: don't "re-purpose" (gotta love that word) 30-second spots from television.