Earlier this year, Palm released the Pre, the first phone powered by its new webOS. The webOS also has an online application distribution method, named the App Catalog. The App Catalog is technically still in beta, so applications aren't admitted as fast and as quickly as in the App Store. Lucky for Pre users, however, they actually own their own phone, and have this ability which might seem magical to iPhone users: you can install whatever application you want - App Catalog or no.
A whole homebrew application scene has sprung up around the webOS, but unlike the iPhone, "sideloading" applications does not require jailbreaking or even rooting. Palm does not prohibit or prevent the installation of non-Catalog applications, and as such, you don't need to crack your (very own and paid for) phone. No 'rooting' of the Linux-based webOS is required either.
The result is that you need not worry about the next update killing your applications. You need not worry about having to repeat the jailbreak procedure after every update. You don't breach the warranty of your phone by sideloading applications. The only difference between an official Catalog application and a homebrew one is that the former will be included in webOS' update dialog, while the latter will be updated through a separate (but centralised) update tool.
The homebrew scene is a community Palm could've penalised - luckily for us, they did not. In fact, the opposite is true; Palm is more or less using the homebrew community as a test bed, contacting developers who have published applications in the homebrew way, and helping them getting their work in the official Catalog. Compare this to the secretive take-a-stab-in-the-dark treatment even official iPhone developers get from Apple. The iPhone homebrew (jailbreak) community gets even less love, as the Cupertino company is actively trying to keep jailbreaking illegal under the DMCA.
What about security concerns? Are homebrew applications safe? Well, the webOS and its Mojo SDK are designed in such a way that an extra layer of security is placed between applications and the underlying Linux-based operating system, but of course, that's no guarantee. What we have to go on is the immense popularity of the homebrew community: from August 5 through September 4, over one million applications were downloaded from PreCentral's Homebrew section alone, and there have been zero reports of applications behaving badly.
I was pleasantly surprised by the speed and fluidity of the iPhoneOS on the 3GS - two things I found sorely lacking in previous iPhone models. Still, there is no way I'm going to buy a phone over which I have no authority, which technically isn't mine, and over which I have no control. I'll continue to wait with buying a new phone until the Pre arrives in The Netherlands, as I prefer my phone to actually be mine - a concept Palm understands, but Apple does not.