Can i track an email (eg: see if a personal email has been read to another Yahoo address) on Yahoo?

If you're referring to an email that you sent, Yahoo! does not have any option to notify you when the email is read by its recipient. If it's very important, however, you can try using a third party such as http://www.readnotify.com/
Can i track an email (eg: see if a personal email has been read to another Yahoo address) on Yahoo?
No, usually Yahoo will notify you if your e mail is undeliverable, but they don't presently have a feature to indicate whether your e mail was read by the addressee.