A commonly held view in any industry is that when faces from outside the usual suspects start appearing at events, then there is something afoot.
Many will remember a few years ago, before Google announced its intention to buy ITA Software, when the search giant's travel ad sales folk that usually prowled the halls of events were suddenly joined by product managers, strategy and project people that nobody had seen before.
Even when senior Google executives were telling audiences from the stage that the company had no intention of "getting into travel", as happened continuously throughout 2009 (and many years before, for that matter), many attendees could sense something was going on.
It was at this time that the phrase "elephants in the room" started being banded around whenever an army of Googlers turned up at an event.
So with Google finally winning its prize (although $700 million lighter in the process), from where is the next wave of disruption going to come?
Fast forward to 2011 and one the next major conferences on the event circuit is the annual EyeforTravel Travel Distribution Summit event in London in a few weeks.
It is a mark of how far the industry has shifted in the past 18 months or so that the likes of FourSquare (general manager Evan Cohen) and Gowalla (biz dev director Andy Ellwood) are given top billing at a travel conference.
When FourSquare was essentially just a game, travel folk wouldn't have given it a look-in.
Now that it - and other such other location-based tools - are becoming important tools for in-resort services to engage with customers, already the seeds of new business ideas are emerging within existing companies.
Check-ins might sound like a pointless concept to many, but as Caesars in Las Vegas has recently shown, couple social media with customer service and freebies for punters and suddenly there is an interesting new idea around brand engagement with guests.
What about some of the other elephants?
The shyandretiring Jim Davidson of Farelogix is one of a number of cheerleaders for the "direct-connect" model.
Whereas for years the standard "future of distribution" debate would centre primarily on the role of GDSs, and often only include their representatives, such is the potential for change in the model that the likes of Davidson and others are becoming important figures in the debate.
And perhaps, finally, the one area where there are such differences of opinion - that of flash sales and the "Groupon-ing" of ecommerce.
Both Groupon (exec director Rajen Ruparell) and LivingSocial (VP new biz Doug Miller) clearly see the potential for grabbing of slice of the travel business through the model, but where once again the wider disruption comes is arguably in changes to the consumer purchase journey.
The existing order was primarily based on search, shopping, purchase and sharing, whereas now the idea is perhaps mixed up entirely - sharing and purchase, without any shopping and search needed at all.
Nevertheless, perhaps a sigh of relief for many in the industry is that Apple, another shadowy figure with a long history of disruption, doesn't appear to be testing out the water just yet, despite the prospect of iTravel lingering at the back of many minds.
NB: EyeforTravel details: exhibitor list, speaker list, registration.
NB2: Elephants in the Room presentation for the Affiliate Window travel conference in March 2011: