There is a filter action, provided by FiltaQuilla, to "add sender to address list", and amongst all the locations offered, your address books are included.

But I don't see any easy way to offer the user a dialogue to allow him to choose whether or not to do this. Maybe a javascript maven could do something here.

Any sender can easily be added to the address book by clicking on his name/address in the received message's header. Maybe you could use a filter just to highlight messages from unknown senders so as to prompt the user to consider adding them to their Address Book. Or you could create a Saved Search to gather such messages. Then their simple presence in that saved search folder would indicate their unknown status.

I mis-read your comment "Any sender can easily be added to the address book by clicking on his name/address in the received message's header. ". I was thinking the option came up by right-clicking the message in the inbox listing at the top of the TB window. I finally got it -- you click on the message header. duh. That will work fine for me.

So, my process will be something like:

• tag the message in a filter if it's not found in any address book
• the user will add the sender to the address book if they recognize the sender address.
• I'll periodically manually copy (and empty) the filter log and process it with a mixture of manual and automated (batch scripts) processing. This needs to be fleshed out.

Of course, the $64B question is "how does one determine -- or even make an intelligent guess-- whether the sender address is legitimate?"

Thanks for your help, Zenos.