An Anti-American Boycott Is Growing in the Arab World
American support for Israel is driving grass-roots effort to punish America by boycotting its consumer products throughout Arab world; word is being spread via Internet, mosque sermons, fliers and even mobile phone messages; purchases of American goods generated by 300 million Arabs form very small part of American exports, but long boycott could retard spread of franchises and other products; boycotts are largely effort of individuals and small groups without government involvement; they reflect growing sentiment that Arabs should distance themselves from United States, and they want their governments to do likewise; photos (M)