No, you aren't giving away your SID. The random-looking number is the ASIN of the product. (You could have reassured yourself by reasoning as follows: everythin

No, you aren't giving away your SID. The random-looking number is the ASIN of the product. (You could have reassured yourself by reasoning as follows: everything apart afrom that final number clearly contains very little product-specific or user-specific information; and there surely isn't enough information in a 10-bit number to identify both a product and a user uniquely.) I don't think it's reasonable to expect Amazon to have product URLs with no random-looking unique ID in at all, and 10 digits seems pretty modest. But I don't see why they couldn't make http://www.amazon.com/ASIN/0961392118 http://www.amazon.com/ASIN/0961392118 take you to their main page for that book.