Yes, I'm talking about MacBooks. Last year there were just a few among the 700-odd attendees. This year, among the 500-odd people attending the conference, there are lots more.
I asked a few of those who were carrying around these shiny laptops why they were using a Mac at a Linux conference; wasn't Linux enough for them?
Web developer Jeffery Fernandez, who is employed by Internet Vision Technologies in Melbourne, said he had a Mac "because everything just works."
The hardware was top quality, he said, adding, however that he had a Linux distribution, OpenSUSE ("I am a big fan") running within VMWare. So he wasn't exactly bereft of Linux.
"Only because it's pretty," smiled James Page, senior systems administrator at the University of Southern Queensland, when I asked him the same question.
He did have some serious reasons: the Mac was what was available at his workplace. He had two choices - the Mac or Windows - and chose the former because he needed an X term.
His Mac has a Fedora installation set up as a dual boot but he said the wireless connection with Fedora was rather flaky and managing the brightness of the display was a problem as well.
Famous people use the Mac too. Rasmus Lerdorf, the creator of the PHP programming language, said he had bought a Mac because he could not get a non-Windows laptop. And he was certainly not willing to pay the Microsoft tax.
Lerdorf uses the Mac all the time; he has a Linux VM running which he uses for development. His co-location server runs Debian.
For Neil Cox, a senior IT professional who provides support to small businesses in Canberra, the one reason for a Mac was great hardware. And Cox has no use for OSX - he has stripped it off and is running Lenny on the Macbook.
"Great hardware," he said when asked why he had a Mac. "I've bought Macs since 1985. Had one Dell laptop and didn't like it."
Cox is a command-line person by and large but said he occasionally used GNOME.
Louis Suarez-Potts, community manager for OpenOffice.org at Sun Microsystems, said he was a Mac user because "much of what I do requires tools that are reliable." He also runs Linux in a virtual machine, using VMWare for the purpose.
James Turnbull, who works as a senior network specialist with a big Australian corporate, said he was using a MacBook simply because he had gotten into using OSX at a stage when both GNOME and KDE, the two most used Linux desktop environments, were "not at their prettiest."
"I have a dual boot with Ubuntu," Turnbull said. " The Mac is a good piece of hardware. But my next buy is going to be one of the netbooks on which I'll put Linux."
I asked two other conference attendees for their input but they did not wish to be quoted.
There were quite a few others I spotted running Linux on the Mac. It looks like Apple need have no worries that Linux will lower its sales numbers.