I posted a question about about installing libmcrypt on Snow Leopart, & it was replied to, but the the suggestion in the reply didn't work & I feel like I need to add information related to what happened, the output of a command. However, the # of characters in the reply box is too small for me to add this information. What's the proper way to add a long reply? Do I need to edit the original question to do it?
If your reply at all adds more information to the question, please edit your question and add it.
Comments should not add substantial/important details to a question, that is what editing is for.
If you need to alert a specific user that you did add that information, you can add a comment to the effect of
"@user see the edit to my question".