PortableApps.com has begun distributing freeware apps in addition to open source apps on their site. Today: Skype and Chrome (and others). Coming soon... a whole lot more.
"But wait, Dark," I hear you saying, "isn't open source free as well?" Well, sure it is. When we say "freeware", what we mean is closed-source freeware. While it's free to download and use yourself, you don't get the source code, so you can't modify it, and more often than not, you're forbidden from redistributing it as well. That doesn't mean you can't put it on a CD/DVD with a bunch of other freeware apps and pass it to a friend (well, actually, it does, but nobody will care), it just means you can't put it on your web site. Web sites like filehippo.com that seem to collect the best freeware (and open source) get permission to redistribute freeware.
"But isn't open source freeware?" No... it's not. Open source, per definition, doesn't have to be given away for free. Not only do I have no good examples of successful open source software that cost money, I don't know why anyone would open the source and charge for the software. Seems contradictory to me, but it's not. At least, it's possible. But no, open source is a different kind of license. Open Source, as defined by the Open Source Initiative, is defined here and explained here. It's all very complicated stuff I'd be more than happy to let them explain while I just move on. The open source software you know and probably love, from Firefox, to Pidgin, to OpenOffice, to Linux, is free to download and use and modify and redistribute, although Mozilla opens a hell of a can of worms over open source by retaining trademark to their name and logo, so if you do modify and redistribute Firefox, you have to do so under another name, and you gotta change the logo, too. (See Blackbird, Orca, and Iceweasel for three browsers which did exactly that. PortableApps.com actually acquired Mozilla's permission to keep the name and logo, but that's rare.)
So what does this mean? (Yeah, I know. I say that a lot.) For the past couple years, when portable applications really started to get big, the only legal way to make something portable was to start with an open source program, because freeware can't be legally modified. Portable freeware was often illegal, with very expensive software such as VMWare ThinApp (itself virtually profanity over at PortableApps.com) or Xenocode used to do the work. You could get these programs at a variety of warez sites, sites that distribute various illegal programs, and typically infect their releases with viruses and other nasty stuff. (You don't think they blatantly break the law and advertise it as a favor to you, do you? Don't ever think that they don't want something in return, that they won't lie about their motives, and that they have anyone's best interest at heart but their own pocketbook.)
Now, some popular freeware programs are going to be available in a portable setting. Which is ironic, because all software starts portable. It's got to be tied to the registry or something like Microsoft's .NET Framework for it to not be portable. But once it is, the wizards over at PortableApps.com design launchers that make the programs think they're installed, when they really aren't. This virtualization adds very little, in some cases nothing, to the resources required to start and run a program. Unless you have a slow flash drive over a USB 1.1 connection, you won't see much of a difference. If you run portable apps from a regular hard drive, you will not see a difference.
Why run portable apps from a hard drive? Well, say Windows messes up. For any reason. It's Windows. Messing up is what it does best. Now you could take it to the repair shop, you could fight with it, but wouldn't you rather just solve all your problems in one hour flat? Yes, you can. You need a second hard drive. Merge to portable applications. You don't need the PortableApps.com Platform (menu) but it can be helpful. (It would be more helpful if it had categories/folders, but that's not a feature that's being planned, though maybe with the application directory expanding with freeware, maybe it'll be considered in a future version.) Start using the second hard drive for all your pictures, documents, music, and video files. Get yourself to where you have nothing on your C drive but Windows, your antivirus, your firewall, your drivers, and your programs that aren't available portable yet.
Once you're at that point, once Windows really starts acting up, just ensure everything is off of C, put your Windows CD/DVD in, reboot the computer, and follow the prompts to erase the C drive. Reinstall Windows. Reinstall your drivers (including DirectX), then your antivirus and other security software, then your non-portable programs. Your portable programs will be in the same place you left them, ready to go as ever.