I have noticed on a thread where I have had some comments that the comments on the OP and another persons answer are gone. I didn't delete them so why would the be deleted?

One comment was about a term being -243 and another was about the use of Wolfram. Therefore, the comments didn't warrant deletion by a moderator so why would they be deleted?

• just in case, go back...yesterday the thing died briefly while i was composing a long answer, it took several screens before i could find one with my draft. Also, if I leave something and go back using the web return button, new stuff is not present until I refresh the page – Will Jagy Nov 13 '14 at 19:40
• @WillJagy these comments were present since people responded to them and I back in response, but now they are gone and I didn't delete them. – dustin Nov 13 '14 at 20:23
• There is not much that anyone can say without knowing where these comments were. – robjohn Nov 13 '14 at 21:08
• @robjohn they were here – dustin Nov 13 '14 at 21:13

A comment that points out an error to a post that is subsequently acted upon (by, e.g., editing the post) is then obsolete and can be deleted because of that. In the case of your "$-243$" comment, it was flagged as being obsolete (since the question was appropriately edited) and I deleted it (along with a couple others that similarly served no further purpose).

Your Comments are still there. It's just that when an Answer (or Question) gets a certain number of Comments, the system hides some of the unvoted Comments so that space is saved on the page. Look for a link below the visible Comments that says "3 more comments" or similar.