How might Ubuntu become more appealing for Adobe to make their creative tools available on this operating system? (Their Creative Cloud, Creative Suite, and apps.)

Here are some considerations, observations, and... a little enthusiasm!

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It is a given that Ubuntu could become more popular and widespread. At even 3% user base worldwide, it would still have a few points to rise to match OS X's 7 - 10%. However, it could happen. Especially considering the following aspects.

Canonical seems to be focusing on making Ubuntu more polished as an overall experience. They've even said that as of 13.10, they have committed personnel to working on precisely this. As time progresses, Ubuntu can only become a more formidable end product.

With Unity's desktop-mobile convergence, Canonical have been ironing out and beautifying the Ubuntu experience; making it both appealing and easy-to-use for the average user.

Ubuntu's switch to Mir sets it apart from the rest of Linux. By offering a smoother and more seamless visual experience, this could be one element that helps lift it out of distro obscurity. Canonical's initiative here brands them as more of a venturing enterprise -- with 'customer' interest -- versus the more moderately-paced community ethos which generally pervades Linux.

With these efforts combined, Ubuntu is making itself more targetable as a brand; one which could eventually stand alongside other well-known names.

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Could Ubuntu become what is the next open source Apple? Would Adobe then make its creative tools available? Are there any overlooked obstacles that might hinder Adobe from doing so? (i.e. Open source licensing, system architecture, existing marriage to Windows?)

Who knows what the future might bear. But maybe, by some form, one day Adobe's creative suite will become available on Ubuntu!