So on the Sun/MySQL theme, what are the implications? Huge, to me, absolutely huge, on so many fronts. The positive is that both Yahoo! and Microsoft are big companies that like to innovate.
From the point of view of a PHP developer, it’s particularly interesting. Microsoft has internally changed its view of Open Source a great deal over the last few years. In the PHP world we’ve seen this on a number of fronts, including the partnership with Zend to make PHP run well on Windows, the various Web Developer summits at Redmond (due to Sanjoy Sarkar, a common fixture at PHP events, and all around nice guy Brian Goldfarb, who was the first MS employee to come to a PHP conference, back in 2002 I think). This last week my friend Wez Furlong (of PDO fame) was at Redmond with, as he put it, a "bunch of compiler geeks", speaking at the 2008 Lang.NET Symposium.
Yahoo! is of course the home of a lot of really big PHP, and some famous PHP developers, in particular Rasmus Lerdorf, "the father of PHP", and Sara Golemon. (Andrei Zmievski left last year to join Outspark.) One assumes that the architectures within Yahoo! would continue to be LAMP based, at least in part because the cost to switch would be amazing.
These things come in bursts: I remember Sleepycat/InnoDB/etc in 2006. Now we just have to wait and see who is next.