A website that urged visitors to lower prices for grocery items by substituting bar codes shut itself down after pressure from Wal-Mart. The site's operators, a group of tech-savvy political activists, decided to close the site Wednesday after contacts between their lawyer and those of Wal-Mart <http://www.walmart.com>, the world's largest retailer. http://wired.com/news/business/0,1367,58528,00.html