Around Christmas time UPCZilla began to get a huge amount of interest from the GoogleBot (Google’s crawler that goes around the net collecting content for its index). At one point it was hammering our site big-time, fetching up to ten pages a second. With that kind of load on the site you start to see the bugs multiply. One of them was a lot of dead (404) pages caused by searches yielding invalid UPC codes. These aren’t from our database, they get thrown up when you do a keyword search, and are supplied by third parties who obviously aren’t doing the best job at weeding out invalid codes.
So we’ve fixed that now. You can no longer click on invalid links, instead a little note is inserted next to any invalid link detailing the problem, as you can see in this (extreme) example search.
It will even suggest you add a leading zero to an 11-digit UPC, and give you the correct link to do so, as very often (though not always) UPCs have 11 digits only because someone left the leading zero off. This also often happens when UPCs are stored in Excel tables with the wrong field type – for the record, if you want to store UPCs in Excel and not have the leading zero stripped off you can set the column to a Text field and THEN paste in the UPCs and the leading zeros will be preserved. Strangely, you can then convert the column/fields to the Number type and the zeros will not be stripped off.
In any case I really urge sellers to make sure their UPCs are VALID. One very good reason is that sites like this one will weed out products with invalid UPCs, with the result that your product will not be listed by our price comparison engine and you will miss out on sales.