Just me then I find that people can disguise what they're thinking with body language etc... but it's harder to disguise your actual thoughts through the written word, your mind is more fully revealed. I find I'm more thoroughly attuned to changes of tone in written language than I am with spoken. Ho hum
I find the written word as discourse can be very easily ambigous, hence the development of the smilie to assist the exchange of ideas. A written dissertation (?) could be more revealing of the writers thoughts, do they not have to decide what they think before they can write ? Or too much bud !
I often find that the way people write things and what they select to say/not say reveals more about a person than the content of their writing.