[marginalia_nu]

People who aren't interested leave early. This has nothing to do with attention span. If you cut it to just a few seconds, then yes more people will watch the whole thing, but that doesn't mean more people will get anything out of it, it's just they don't have time to move on before it's over.

[namanyayg]

I think you're missing the fact that interest can be piqued by a good video, it is not predecided if someone is interested in a particular product or not