When I get a notification regarding a comment I posted how can I find the comment again and the response?

I've been wondering this also recently..

All questions the past week,or so have been disappearing after about an hour;Leaving only questions posted a week ago..

What you need to do is click the star under the question to follow it,even if the question disappears you will still have access to it.

As far as I know, they don't send out any sort of notification like that, but I wish they did because it would sure make things simpler. I always have to check my answers to look for comments.

Yahoo! Answers (formerly known as Yahoo! Q & A) is a community-driven question-and-answer (Q&A) site or a knowledge market launched by Yahoo! on June 28, 2005 that allows users to both submit questions to be answered and answer questions asked by other users.

The same way you will be notify again if someone answered your question again. Or it's better go to your exact question & look at all answers that one you've been received on this question.

Click on the link in the e-mail