My experience is the same as eits...you hit the back button to go back to the previous screen. If you're out of "back screens" in your app, it will take you to the previous app (which is what is being demoed in the article you're showing). I've read those "it's unpredictable" articles, but truthfully never really experienced the issue.
Unlike my brother Ichinisan, I've been iOS-free and using Android now since 2011 and I could tell you that this is absolutely wrong. I encounter problems with it every day in multiple apps. Often, it's bad app design but the most damning example is Google's own Google Voice.
First of all, Google Voice stupidly does not integrate with your native Messaging app like iMessage or SMS GV Extention can on an iOS device or BBM on a Blackberry device or Windows Live Messaging on a Windows Phone 8 device. Oh, it has an "Integrate with Messaging" option that SOUNDS like it does what the rest of the industry has led you to expect, but all that does is configure forwarding to your native number at your carrier's rate without all the warnings the website would have given you when setting up the same thing. $30+ later in texting overage charges and I now know better. Now, unlike messaging, it integrates with your dialer just fine and shows merged call history, missed calls, and even transparently makes all outgoing calls from your GV number (your recipient shows in the call history instead of a GV access number). Nice. Why couldn't Messaging integrate a little better? Now, when I want to use the GV app for text messaging, I have a ton of other call history crap breaking up my messaging history and making it difficult to find anything. I have all that where it belongs: My dialer's call history. I don't need it when I launch the app. Ever. Some people might depending on what they do with their GV account and incoming calls, but I don't. Unlike the Maps app that has other icons in the app drawer for launching straight into certain parts of it like Navigation and Latitude, there is no (obviously needed) icon for launching straight into GV SMS, GV VVM, etc. Yes, because Android has no standard Visual Voicemail, which I want, and because I want all my VMs consolidated, I forward my native number's VM to GV also, which only adds to my clutter when launching the app.
WAIT A SECOND! I thought I was talking about the back button. I am. Here we go: The only way to prune through the mess of needlessly consolidated GV call history, VVM, and messages is to go to the inbox, press menu key or action-overflow softkey, and select labels, then filter with a label. The VAST majority of the time, the app is not in the inbox when you launch it and is, instead, showing the last conversation you had or voicemail you listened to. That would be fine if there were a way to get back to the inbox or to go straight to labels, but you can't. You are where you are because it remembers where you were when you were last in GV and also because the notification jumped straight into it when launching the app, bypassing the inbox. If you were doing something else between message exchanges, you were likely sending your quick response and going right back to it, which I often do using recent apps or by going to the home screen (depends on what I was doing). IOW, I don't always use "Back." When another message comes in, I get my notification, jump to it, respond again, and return to what I was doing. Often times, I delay my response so that I can do whatever it was that I was doing and I get a couple messages from different people to respond to. When I tap the notification and jump to one of them, I have no elegant way to get back and respond to the other... or even see it! All GV notifications are cleared as soon as I return to the app instead of when I view the particular message, so I can't jump to it (more on that later). When I press "back" it leaves the app and returns to what I was doing, be that another app or the home screen. When I launch the application manually from the home screen which dumps the "between applications" back buffer I am still looking at the last conversation I had. When I hit menu/action overflow, I have no option for jumping to "inbox" or other labels. When I hit "back" again, I am STILL looking at the same conversation. Why? Because I actually dared to use my notifications menu to respond to my notification multiple times for multiple responses. :rolleyes." Each time I did it, it opened another instance of the same conversation within the app. To get back to the inbox I have to press back multiple times until it leaves the app and then launch it again.
Now, what if I didn't even know there was another message in the inbox because the notification dismissed automatically when I responded to another one? This happens CONSTANTLY. Google needs to fix Android's notification system so that there can be a history of notifications even from the same app. GV somehow combines all unacknowledged notifications and dismissed them all at once, but even that dismissal wasn't necessarily a user acknowledgement. Remember when I said that it clears all GV notifications when I respond to one? It actually clears all GV notifications just from being in the app EVEN WHEN THE PHONE IS LOCKED. This is inexcusable. It's bad enough that I may be actively texting with someone and receive a text from someone else that I don't know about and have no way to go back and see/check, but it's even worse that I have to leave the app between every text to make sure it doesn't happen and EVEN worse that I have to use the back button when I may want to go someplce else on my phone. Yes, if you text someone and lock or set your phone down while waiting for an expected response, you will not get a notification for any other texts or voicemails. When you get a message, the notification plays a sound and the status bar icon shows up for a fraction of a second but disappears before you can even look at it, much less, finish responding to one, swipe the notification menu down and acknowledge or dismiss it. My phone has the ringer turned off at work so I don't even get the sound before it automatically dismisses the notification, but even when I do hear the sound it was in a flurry of other notification sounds that I expected or it was received simultaneously with another. If you were expecting a reply and unlocked your phone to find it, what indication is there that you have another one? None. Even if you could hear each one and the settings were such that it doesn't notify twice and the number of notifications was correct because none played simultaneously, is Google ACTUALLY expecting me to COUNT audible notifications so I can know to leave the app and relaunch it (sometimes several times) to get back to the inbox!? Madness.
One thing I didn't mention is how the service screws up everything and exacerbates the back button problem when it needlessly tries to split conversations. If you messaged me yesterday, then my mom messaged me, then you messaged me today, I will see three conversations in the inbox. If I need to go back and look at something you said yesterday to reply to it, then I can do that. No biggie, right? Except that I dared to convenienrly reply to you from the previous conversation I was reading that had a reply box! Now my incomming texts are randomly going between two threads that I can't properly switch between and I can't even read or jump to from the notifications menu! I once worked out a work schedule change with someone who changed his mind several times and this made it a NIGHTMARE to prove that he was wrong and simply did not show up to what he agreed to do. Nothing was chronological and eveything was split randomly across ten different threads with no time stamping and only a conversation date that was completely useless once the conversation involved multiple days weeks apart. I was right and he was responsible for the no-call/no-show, but he had no such confusion on his phone (simply forgot to ask if I would work a particular day for him). There is absolutely zero reason to not have one thread per contact like everything else similar in this world. If they insist on splitting into threads to intersperse with call logs and VMs, the least they could do is close out previous convos with the same person and link the reply to the new one or disable the reply field in an old one, but that woouldn't fix everything. You'd think that screwing up its own function for a useless threading feature like that is bad enough, but it get worse: A long message is often split up into multiple, and sometimes they branch and form TWO current threads! I wish I were kidding. Othertimes it's like half of the message dissappeared into the ether because that thread never got a response, which is another huge issue: It only forms threads for incoming texts! If you don't get a timely response that forms the new thread, you have no record of the sent text! Absolutely intolerable. Knowing what kinds of problems it can cause with other missed notifications, I sometimes deliberately leave my phone in the app with the sent message on the screen until I get a response. If I have to leave it, I sometimes resort to taking a screenshot before leaving so that I have a record on my phone. My phone is only capable of screenshots because I loaded problematic generic international firmware on it, so bad experience, interface, and design strikes again.
The native texting app isn't made like that. I wouldn't even have to complain about their implementation of notifications and the back button if they TRULY integrated it with the native messages app (like everyone else) or made a VVM and text app launcher/shortcut. Why does Google let the GV team get away with being so dumb/sloppy? Not only is it expected/demanded, but it is the main reason I would consider going back to iOS. SMS GV Extensions means that GV works and integrates better on jailbroken iOS than it does on their own OS. It could also compare to iOS' Visual Voicemail with a different app icon that jumps straight to it. A similar one for texting would let me replace the native one, since I can't integrate with it, and would finally allow me to cut through all the misseed calls and voicemails when I just wanted to text or look up a text. It should also allow you to bring up a per-contact chronological text history like every other phone (WTF is this threading clusterfu*k supposed to do?!).