Microsoft has once again sent a congratulatory cake to Mozilla, this time for the release of Firefox 5. This is the fourth cake the software giant has sent; it's become a tradition that is celebrated upon major version releases of the open-source browser.

While it's not really a huge deal, it's worth noting that the cake Microsoft sent this time is noticeably smaller. It appears that the company is trying to cut costs (Mozilla has announced it is releasing at least four major versions this year), is poking fun at the fact that a major release of Firefox is no longer really a big thing, or both.

In any case, here is the relevant tweet from Damon Sicore, VP of Engineering at Mozilla, and an accompanying picture:

Just received the congrats cake. From all at Mozilla, thank you, Microsoft. We love you, too. :)

The tradition began in October 2006, when the Internet Explorer 7 development team sent a cake to Mozilla for successful shipping Firefox 2. Given the state of the browser wars at the time, many joked about the cake being poisoned, while others teasingly suggested that Mozilla send a cake back along with the recipe, in reference to the fact that the organization produces open-source software. The IE8 development team sent another cake on June 17, 2008, when Firefox 3 was released. The last cake was sent in March 2011, after the release of Firefox 4.

Mozilla still plans on shipping Firefox 6.0 and Firefox 7.0 before the end of year. Firefox 6 is slated for an August 2011 release. The non-profit organization has promised to push out a new stable build every six weeks, so it's possible we may even see Firefox 8.0 and Firefox 9.0 before the year is out.