Yahoo!'s services vary by availability and rate based on the country where you are located. In order to use Thunderbird with your Yahoo! account, you can configure Thunderbird either with the POP protocol or with the IMAP protocol.
To export your contact list from Yahoo! and import it into Thunderbird:
On your Yahoo! Mail page, click on Options (in the upper right corner).
Select Mail Options
On the left side of the screen, select Contacts . You should now be in Address Book Options.
Select Export Now (under Netscape/Thunderbird).
Type the security code as shown and select export now. Save the yahoo_ab.ldif file to your desktop or some other place where you can find it later.
Under Tools, select Import and then Address Books.
Select Text File LDIF................, then click Next.
Select the yahoo_ab.ldif file that you previously saved.
Sync your calendar
If you have installed the Lightning add-on in Thunderbird, you can sync Lightning with your Yahoo! Calendar. It means that you will be allowed to read and write your Yahoo! Calendar directly in Lightning (and conversely).