On Tuesday, for example, Microsoft has a keynote address, followed by its own press conference in the official Oracle media briefing area. The one time enemy has been welcomed into the heartland.
Wander out into the expo area and you'll find Oracle's arch-enemy SAP and old rival IBM - the two companies most clearly in the line of fire of Oracle CEO Larry Ellison's keynote address on Sunday evening - happily pitching their wares to the Oracle faithful.
But amidst this group of 'co-op-etiting' (That is so not a word! Please do not try this at home!) rivals there is one very notable absence: Salesforce.com is nowhere to be seen.
Been there, done that
While almost every billboard around the Moscone Center boasts a Salesforce.com advertisement, there are none of the guerrilla marketing stunts of recent years planned this time.
Nor will Salesforce.com CEO Marc Benioff be making a cameo appearance during EIliison's cloud-centric keynote later today as many had predicted he might.
A teeny bit of guerrilla marketing
After all on the 'outbreak of peace' conference call back in June, Benioff invited Ellison to attend Dreamforce, an invitation which the latter accepted there and then.
So the possibility of a return to OpenWorld might reasonably have been assumed to be on the cards even if the last time Benioff was due to appear he found himself unceremoniously ousted from his paid-for speaking slot at the last minute.
On that occasion, he set up a rival court as the 'king across the ocean' in a nearby hotel where proceeded to mount a PR coup d'etat.
But that was all before the rapprochement that we all witnessed back in June.
So if Microsoft - which also kissed and made up with Oracle during that long week of cloudy reconciliation - gets its moment in the spotlight, why not Salesforce.com?
When I caught up with Benioff this week, he gave me a very simple explanation which boils down to: been there, done that, not for us. Or as he puts it:
"I have been there before. I have spent money there. But my customers are not there en masse. They are not walking the halls of Oracle OpenWorld.
"Oracle's customers are database administrators and the Oracle keynote on Sunday night very much spoke to that audience.
"Larry does his keynotes, I do my keynotes, but they are two different keynotes, two different perspectives.
"Our customer from General Electric or Thompson Reuters is not the same person as their customer."
Rather than being a good customer engagement channel, Oracle OpenWorld is a better place for Salesforce.com to go and speak to press and analysts. But then people say he's stirring things up, says Benioff ruefully.
And he wouldn't want that he protests, with a brave, but perhaps not entirely successful, attempt at an innocent expression.
Actually, as we noted yesterday, Benioff was in fact thoroughly approving of Ellison's opening keynote which focused heavily on database and hardware technology. He rejects the criticism levelled by some industry analysts that the presentation had lacked bigger picture vision.
Benioff defends Ellison, arguing:
"That was not the purpose of the keynote. That was the hardware keynote. No-one is better when it comes to databases. Hopefully he will be more visionary about the applications."
That's the kind of sentiment that we'd have been hard pressed to expect a few years ago when Benioff would have been among the most vocal to criticise Ellison's positioning of the Oracle Exadata and Exalogic machines as clouds.
And the inevitable big metal box with the X on the front was on the stage with Ellison on Sunday night, but as Benioff points out:
"He's kind of dropped that one. On Sunday he didn' t point at it and say that's the cloud in a box.
"Larry's narrative evolved on Sunday. He was very much positioning against HANA."
This is a sensible move, reckons Benioff:
"SAP seems to have stopped a lot of its cloud messaging and positioning and is ramping up on HANA.
"That's wonderful. HANA is a great real time database but it is not going to change the industry.
"Larry looks at SAP customers who are running on Oracle and who are saying do I want to stay on Oracle or do I go to HANA and he's given them a way to stay on Oracle."
That Workday announcement
On the subject of staying on Oracle, I asked Benioff about last week's surprise announcement that Salesforce.com would be standardising on Workday's cloud HCM offering rather than Oracle's Fusion HCM as we had all understood would be the case back in June.
Benioff confirmed that Salesforce.com will still be using Oracle's financials in the cloud, but would indeed be moving to Workday for HCM - which is pretty much what we learned last week.
So how then would he characterise the relationship between Oracle and Salesforce.com today as opposed to back in June when the two seemed headed for complete fusion (if not Fusion!)?
Was it, I wondered, best described as detente? Sort of, peace in our time but with both sides still holding on to different belief systems?
It's a description with which Benioff seems comfortable, noting:
"It is just that. I'm sure [Larry will] be competitive on Tuesday in his keynote and do a compare and contrast. And that's fine."
He's also of course completely comfortable with the nature of the Salesforce.com/Workday announcement on the eve of OpenWorld, arguing that this is the way of the world today and what customers expect to happen:
"People want enterprise software firms to work together. Customers are driving us to do this. Take a customer like Thompson Reuters. They use Oracle, they use Workday, they use us. They want us all to work together and to work in harmony.
"We want to work with Oracle, we want to work with Workday. Oracle should want to do that also.
"Oracle may not want to put out a press release about Workday and I can understand that.
"But customers want us to work together and we are doing that."
Benioff will no doubt be watching the main cloud day at OpenWorld with interest and making his views known on Twitter even if he's not there in person.
Now the only question that remains: will Larry make good on his promised appearance at Dreamforce in November?
Disclosure: at time of writing, Oracle, Salesforce.com, SAP and Workday are premium partners of diginomica.