salesforce.com (NYSE:CRM) was started by former Oracle (NYSE:ORCL) vice president Marc Benioff, and the two companies have been fierce rivals in a very vocal way ever since. So when Oracle promised that it would share a "startling announcement" regarding Salesforce this week, the company wasn't kidding.

The week started off quietly as Microsoft (NASDAQ:MSFT) started supporting Oracle's database and middleware software on Redmond's brands of virtual and cloud computing platforms. Just another deal to expand the market somewhat for both parties -- nothing spectacular.

But the promised Salesforce announcement is the real McCoy. This time, we have two extremely public rivals coming together for mutual support of one another's most important platforms. Oracle gains a high-profile win for some less central products such as the Exadata data management platform, and Salesforce gets a very committed partner for its back-end operations. And this agreement is here to stay, with a nine-year term at launch.

In the video below, Fool contributor Anders Bylund explains what this deal does and doesn't mean for the companies involved. (Before you ask, it's not a sign of a pending big-ticket buyout.)

Fool contributor Anders Bylund has no position in any stocks mentioned. The Motley Fool recommends Salesforce.com. The Motley Fool owns shares of Microsoft and Oracle. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.