I can't say that it was totally unexpected, but it did happen rather suddenly. The deal between IBM and Sun collapsed, and Oracle wasted no time in swooping in to pick up the pieces with a deal to acquire Sun for $9.50 a share, or about $7.4 billion. What is surprising is that the deal is really not that much more than what IBM was offering.
The deal, assuming it is approved, will go through this summer, and will give Oracle two key pieces of technology: Solaris, and Java. The Java technology of course is the basis of quite a lot of Oracle technology, including Fusion Middleware, which makes Java very strategic in this acquisition. Solaris too, is a good win for Oracle, since it is widely used to run the Oracle database. What it does with the rest of Sun is really up in the air, and there is a lot of speculation as to what Oracle will do with Sun's hardware business and the MySQL database.
On MySQL, it is open source, so is likely to live on in one form or another, but my guess is that Oracle isn't going to put a lot of energy into it. On the hardware business, this is just something Oracle had to take to get Solaris and Java. We can only speculate at this point, but best guess is that they sell it off. But regardless of whether Oracle jettisons Sun's hardware or keeps it, there will be a big impact on Sun's sales channel.