If so, you need SAP Universal ID. In a few months, SAP Universal ID will be the only option to login to SAP Community. Without it, you will lose your content and badges. If you have multiple accounts, use the Consolidation Tool to merge your content.
When we maintain more than 2 email addresses in vendor master record, we observed that the email address in the first line is being picked for sending PO emails. What is the use of "Standard Number" radio button ?