Linux users have recently been celebrating the arrival of an official Photoshop for Linux-- yup, once Adobe's Photoshop-streaming-via-Creative-Cloud is out of beta for Chrome, Linux users will be able to use Photoshop in an official way.
But Adobe hasn't suddenly fallen in love with Linux. In fact, whatever support they provide for Linux seems purely coincidental. Adobe has been going out of their way to kill their consumer Linux software in the past few years: Reader, Flash, and AIR for Linux have all been axed.
Adobe Reader has never been the nicest PDF reader for Linux. It's always been behind Windows and Mac. But Adobe did provide an official PDF reader for Linux. It was long stuck on version 9, while Windows and Mac are up to version 11. But as a reddit user noticed a few weeks ago, Adobe Reader for Linux is no longer available for download from Adobe's website. This isn't a surprise, as they're no longer officially supporting Reader for Linux--it almost certainly has security vulnerabilities that will never be patched.
As a normal Linux user, you probably don't care too much. Linux distributions include good, integrated PDF viewers like Evince for GNOME and Okular for KDE. Chrome and Firefox have their own PDF viewers. Adobe Reader is clunky and not as nice to use, so you may have never used it.
But Adobe Reader is sadly still necessary. It supports "extended forms" that are often used to fill out government documents in PDF form, and no open-source PDF reader for Linux supports those. It also offers other features like animations and embedded 3D models. Yes, all this complexity leads to security problems in a document format that was originally supposed to be simple. But if you need to fill out government documents in PDF form, you probably can't do it on Linux anymore. There's simply no alternative to Adobe Reader here.
Adobe transitioned to maintenance mode for the standard Linux Flash player plug-in back in 2012. If you're using Firefox on Windows or Mac, you have Flash Player version 15. If you're using Firefox on Linux, you have version 11.2. Thankfully, Adobe is still providing security updates to this old version for five years, so users have until 2017 before the plug-in is completely unusable. Some Flash content does require a more modern version of the Flash player, however--it's completely unusable in Firefox and most other browsers on Linux.
Linux users do have an option here. The Linux version of Chrome comes with an up-to-date Flash plug-in that uses the Pepper plug-in API. Mozilla has no intention of supporting this new plug-in standard in Firefox. Chrome is your only option for an up-to-date Flash plug-in on Linux--although you can manually hunt down and install the Pepper plug-in for Chromium and Opera. Chrome is based on the open-source Chromium code and so is the latest version of Opera for Linux.
Chrome on Windows and Mac also provide a Pepper-based Flash player. However, for Windows and Mac, Adobe is still releasing modern versions of Flash for NPAPI (Netscape Plugin API) browsers like Firefox and Safari.
Adobe also ended Linux support for Adobe AIR with version 2.6 back in 2011. Adobe AIR is a runtime for building "rich internet applications" and deploying them as desktop apps. At this point, you might be thinking "Who cares? Flash has performed terribly on Linux anyway and I don't want those AIR apps on my desktop." And you'd be more or less right. Linux users didn't really want Adobe AIR apps, and Adobe didn't want to support AIR on Linux anymore.
But this decision is still affecting game developers today. It really hurts the selection of Linux games on Steam and elsewhere. Any games programmed with Adobe AIR will run just fine on Windows and Mac OS X, but the developer probably won't be able to port those games to Linux. You may not even know it was Adobe AIR's fault--you'll just see a game that only supports Windows and Mac in Steam and pass over it.
For old Adobe AIR games on Steam, the lack of development on the runtime is causing problems. As the developer of Incredipede put it:
"Incredipede uses Adobe AIR and Stage3d for graphics card support. Adobe has not written graphics card support into the Linux version of AIR so the game can only run with software rendering which is much slower. To compensate I have to turn off a lot of the fancy graphics."
And, as the developer of Bardbarian explained when asked if they could add Linux support:
"Unfortunately not :( We really wish we could, but this is built with Adobe AIR, which does not support Linux."
Adobe AIR games are even causing problems for Valve's SteamOS.
Yes, you'll be able to run Photoshop on Linux and the latest version of Flash is still on Linux if you use Google Chrome. But, when looking at Adobe's gradual axing of all their consumer Linux software, this feels like an accident. If not for Chrome, Linux users would have nothing.
This is especially sad because it's not the software itself that matters. It's all those PDFs with extended forms, websites using Flash, and games written in Adobe AIR that are becoming increasingly unusable on Linux. Adobe's platforms--PDF, Flash, and AIR--are no longer the cross-platform tools they were originally promised to be.