As thousands prepare to descend upon San Francisco and the legendary Moscone Center for Oracle's OpenWorld Conference 2009, intrigue swirls regarding a surprise guest. \n\nThe lineup of keynote presenters offers both what you'd expect (Oracle presidents Charles Phillips and Safra Catz on Monday morning; CEO Larry Ellison closes on Wednesday) and a couple of A-List high-tech heavyweights (Scott McNealy, Michael Dell and HP's Ann Livermore). \n\nIt's hard to imagine how Ellison can top his recent appearance and highly entertaining "Cloud Computing" rant. Oracle CEO Larry Ellison speaks to the masses.But the blogosphere is swirling with an unusual development: Salesforce.com CEO and Ellison protog\u00e9 Marc Benioff will reportedly deliver a keynote address, according to Enterprise Irregular blogger Josh Greenbaum. (Greenbaum says Oracle has confirmed this, but the OpenWorld presenter list does not list Benioff.) \n\nRead the Enterprise Software Unplugged Blog \n\nGreenbaum terms Benioff's presence (and rather large Salesforce.com booth at the Moscone center) "the fox in the hen house." Another fox sniffing around will be Seth Ravin, CEO of Rimini Street, the provider of third-party maintenance and support for Oracle and SAP applications. \n\nBeyond all of the glitzy keynotes (isn't it strange that conferences offer more than one keynote?), the annual Oracle Kool-Aid-Fest comes at a time of turbulence, uncertainty and change for Oracle and its customers. \n\nThe worldwide recession has had multiple, arresting effects on Oracle customers, as Ellison has publicly acknowledged: IT budgets have been slashed; executives have pulled back on spending for new software licenses, projects and upgrades; enterprises have refocused their attention on which IT applications are delivering value and which aren't; and enterprise software maintenance and support fees are under the microscope like never before. \n\nOracle's recent quarterly results bear that out: New software license sales fell 17 percent year-over-year and revenue fell by 5 percent, yet Oracle's profits rose by 4 percent year-over-year, relying heavily on the maintenance business cash cow and its 90-plus percent profit margins. \n\nFor enterprise software customers at the show, one big topic is going to be the status of Oracle's Fusion Applications Suite\u2014the much-hyped and long-delayed killer enterprise application suite that combines the best ERP features and functionalities taken from Oracle's expansive E-Business Suite, J.D. Edwards, PeopleSoft and Siebel product lines. \n\nThe OOW theme this year is: "Come with questions. Leave with answers." For years, Oracle's customer base has had too many unanswered questions about the functionalities and delivery date of Fusion Apps Suite. \n\nQuestions most likely won't be in short supply. Attendees are hoping the answers won't be, either. \n\n[Editor's Note: Thomas Wailgum will be at OpenWorld 2009. E-mail him here with any hot topics or insights you have from the conference. You can also follow him on Twitter: @twailgum.] \n\n Do you Tweet? Follow me on Twitter @twailgum. Follow everything from CIO.com on Twitter @CIOonline.