There is a lot going for Linux in business already: it's free, runs well on old hardware, and has a good range of office software, but I don't think business is where Linux will take off, if anything I think it will take longer than home use.
Unfortunately, I think one of the main reasons for Linux having such a good chance is Windows 8. It's a train speeding out of control and hurtling towards the busy station at the end of the line that is release day. I don't say this because I dislike Metro, in fact I think it's a wonderful interface to use on a phone or a tablet, but it completely breaks down when you get to a desktop computer.
In Microsoft's ideal world we all have the big all-in-one touch screen desktops that manufacturers seem to have been pushing in recent years, but how many people have those machine? And how many of them want to sit with their arms reaching out in front of them all the time to perform operations that they could just use their mouse for? I certainly don't want to. Metro is nearly impossible to use with a mouse exclusively, which pretty much rules out upgrading any normal desktop to Windows 8.
Why don't people switch to Linux? "It doesn't do games.", "It's impossible to use!", these arguments are becoming less plausible all the time, and Microsoft should be worried. In terms of ease-of-use, Canonical have been making huge progress in recent years, and I would argue that the current release of Ubuntu is one of the easiest to use operating systems I have seen. For this reason it's not something I would use (at least not in it's out of the box configuration) because I don't want a photo browser, I want a code editor, but for most people it's perfect.
A few years ago the Ubuntu development team made a list of every little annoyance they could find. Things that, in themselves, were so small and trivial that they almost weren't worth fixing, but they went through and fixed every one they could, re-thinking how an operating system should work from core principles of user interaction, and the result is amazing, an OS to challenge the 'king' of user experience: Apple.
It doesn't stop at user experience though. Ubuntu now has it's own 'App Store' like service that makes it easy to install applications for almost anything, no more compiling from source and managing dependencies. For several versions now, as far as I can tell, Ubuntu has required no knowledge of the command line, no knowledge of how to partition a disk, it's really a consumer OS now.
But all of this doesn't really help the fact that people don't know about it. A surprising number of people have heard the name 'Linux', but unfortuantely many people don't even know what an operating system is, let alone what Linux can actually do for them. This is not where Linux will take off.
I think the future of Linux lies with the 'PC enthusiasts', or gamers. Typically gamers have shunned Linux like the plague because the best game it had was Sokoban, and the graphics drivers were so terrible that nothing would run properly on it, barely even the 3D desktop environments that some distributions ship with. But for several years now this has been changing. The Humble Bundle has been selling bundles of Indie games for a few years, and each game has been distributed on PC, Mac, and Linux, change seems to be coming.
Several days ago, however, Gabe Newell of Valve Software commented on Windows 8 being terrible, and said that Steam would be coming to Linux. Valve clearly considers these two facts to be related. This is really big news.
Valve make some popular games such as the Half-Life series, Left-4-Dead, and Portal, but that isn't the important part. They make Steam, the game distribution service, which due to it's community, social networking features based around games, achievement systems, DLC store, and other cloud features, is becoming a gaming platform itself. I'm waiting for the day that we see a new game announced, not for "Xbox, PS3 and PC", but for "Xbox, PS3 and Steam". I don't think that announcement is far away.
At the moment most major games are developed using a Microsoft technology called DirectX. This is great for developers, but only works on Windows. OpenGL is an open source competitor that is the standard for 3D software on OS X and Linux, but because of the lack of a gaming market on those platforms it hasn't taken off for many of the large gaming titles. If Steam is on all of the platforms though, and if developing with one technology can get a game on to all 3 platforms, this becomes a serious possibility for developers. Another historical reason for not using OpenGL was the apparent poor graphics performance, but in porting Left-4-Dead 2 to Linux, Valve recently blew this out of the water, creating a port that was 14% faster on Linux, and even provided large performance benefits when the OpenGL work was brought back to Windows. If I was a DirectX developer, I would be worried about my job.
'PC enthusiasts' love their Windows though don't they? Well I'm not so sure. I think I would have considered myself in this group when I was about 15. Some of the important things are being able to play games (check), install software for pretty much anything that you can think of (check), and customise your system, and this last one is where Linux really shines. Not to mention, being free, it's perfectly suited to high school students with no money. I remember the shock of spending £125 on Windows Vista (hey, it seemed like a good idea at the time).
Will taking the enthusiast market really help Linux though? I remember when I was a teenager, and the household 'techie', my opinions on computer matters ended up having a real effect on what my family did. I liked Macs, and so my Dad, brother and sister all ended up getting them. If I had been a Linux nerd, they wouldn't have got shiny new Macs, I may well have installed Ubuntu on their old computers to give them a new lease of life.
Every non-technical person has a techie that they go to for their computing help, whether it's removing viruses, upgrading their RAM, or working the DVD player (I know it's not a computer, but they never seem to). If you convert the techies, you get the rest of the market along with them.
Linux becoming mainstream will take a few years. Gabe Newell said Steam didn't come to the Mac because Valve wanted it there in 2010, they moved in 2010, because they knew in 5 years time the Mac would be a much bigger platform that they would want to be established on. I'm betting the same thought process is behind the move to Linux. Uptake will be slow to begin with, but as game developers realise that Linux can't be ignored as more and more people leave Windows 8, Linux's marketshare will rise.
2013 may not be the year of Linux going mainstream, but it could be the start.