When the document is saved the license key of the Qlikview installation is embedded in the document.
1. In the above case the user refers to the User Account through which the user has logged in or the email id used while downloading personal addition?
No, the user account on the computer where the user is using Qlikview Personal.
2. Also if the license is tagged to the PC, would formatting the PC and downloading the new Qlikview version would let me open the document created on the same PC prior to formatting ?
No, the Qlikview PE installation needs to have the same license key as the key that's embedded in the document. Reinstalling Qlikview PE will create a new license key. So does recovering a document that contains a license key that differs from the license key of the Qlikview PE installation.
There is a license key for all types of editions (leased license, user license) including personal edition - personal addition has its own and is part of the software.
If you have a persobnal edition you can only open up qvw files that the specific personal edition created. If you have the more true expanded license, you can open up qvw files created by other suers including personal edition