Chris J. Davis [1] ported an MT feature to WordPress; while you type your comment into the textarea, you get a real-time preview. I like that feature, since that simplifies the form by dropping the preview input button.
But instantly I had that other random thought; a javascirpt transforms the entered text into the preview. As long as you do not copy-paste any prewritten text, writing comments usually takes quite a while.
Now, the time argument could eventually be used to prevent comment spam in some way. If the spam is posted automatically, the time used, is probably around zero or marginal compared to handwritten text. Maybe this could be just an additional method. What do you think?
[1] http://chrisjdavis.org/index/2004/03/15/live-preview-for-comments/463/
