Technology in terms you understand. Sign up for the Confident Computing newsletter for weekly solutions to make your life easier. Click here and get The Ask Leo! Guide to Staying Safe on the Internet — FREE Edition as my thank you for subscribing!
Assuming you mean Yahoo Instant Messenger (YIM), then I believe it’s just the contents of a specific directory.
I’d look at: C:\Program Files\Yahoo!\Messenger\profiles\name\Archive, where name is replaced by the screen name you’re using. Remember that Yahoo’s archiving needs to be turned on (it’s off by default) and that also by default YIM will automatically delete messages after 10 days.
How do I backup my Yahoo! Mail? - Backing up web-based free email is important. It isn't obvious how to backup Yahoo! Mail nor is it necessarily officially supported, but it's not hard.
Archiving – What it is and why you need to start - As our lives become more and more digital - from digital documents to photographs and videos - it's time to become a little more intentional about how we keep and manage all the digital data that we're accumulating. It's time to think about archiving.