Zazzle requested also a Tax ID (line 6 of W-8BEN), however this is not required according to the instructions provided by the IRS:
Line 6. If you are providing this Form W-8BEN to document yourself as an account holder with respect to a financial account (as defined in Regulations section 1.1471-5(b)) that you hold at a U.S. office of a financial institution (including a U.S. branch of an FFI) and you receive U.S. source income reportable on Form 1042-S associated with this form, you must provide the TIN issued to you by your jurisdiction of tax residence identified on line 3 unless
Zazzle is not a financial institution and thus this is not a financial account. Correspondingly, the information in Line 6 (Tax ID) is not required.
The income from zazzle is not an US Source Income reportable on Form 1042-S.
so Why Zazzle insists to get this TAX ID ?