I had a look at this concept about six months ago, I found it very interesting. I thought putting up a message that flashed at .2ms. The naked eye would never see it but the subconscious would. The mind would associate the image with the subliminal message.
Vertical text writing is interesting as well. The mind apparently picks this up very quickly. Both on a conscious level and subconscious level.
Colors too can have a profound affect on the mind. For example, yellow seems to be the color one always first sees.
Pretty wierd stuff. greek39