point 1: how do you know where the paragraph begins and where it ends to add the <p> tags?
point 2: if the user is supposed to add html tags by himself, don't add html on his behalf then.
What you are talking about now, and what I am refering to are two different things; you want an option that the user can select consciously and it will add tags for his post. I'm refering to adding tags by default for new users who don't know that they can format their texts in HTML so that <quote>"not-xhtml-aware posters could write clean posts to read."</quote>. That's what you refered to in your original post.
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