The Firefox team received a cupcake from the Microsoft Internet Explorer team on the day Firefox 6 was shipped earlier this month. Mozilla's Firefox Engineering Director Johnathan Nightingale posted this picture in his Flickr account:
And this is the message attached to the picture:
"Every time Mozilla releases a version of Firefox, the IE team sends us a cake. They're cool like that.
"As the releases have gotten faster and leaner... so have the cakes."
"Rumor" has it that IE used to send a cake with every Mozilla version release. But when the releases became more frequent (therefore, lesser new features), the cake became... cupcake!