Multichannel gifts marketer 1-800-Flowers.com and American Greetings Corp. have entered into a strategic alliance that will make 1-800-Flowers the exclusive seller of flowers on AmericanGreetings.com and its sister Websites, BlueMountain.com and Egreetings.com. The two companies will share revenue from the sale of 1-800-Flowers merchandise on the American Greetings sites.