Since chat is a new, free part of the new Yahoo! Mail, its system requirements are the same.

Chat in the All-New Yahoo! Mail with:

• IE 6.0 thru IE 8.0
• Firefox 2.0.1 and newer
• Mozilla Suite 1.7

Operating Systems Supported:

• Windows 2000, XP, Vista, and Windows 7
• Mac OSX or later

To chat in Mail, you’ll also need Adobe Flash Player 9.0.115 (or higher). Click here to check what version you’ve got!

If you need a newer version (it's free), you can download and install the latest Flash Player here.