Re: Jolly Good Journalism, El Reg.
I have published source without including or mentioning a license and I just leave the users to figure it out, but that is probably not the best way to handle that.
Definitely not, it may also discourage people from using it. I certainly wouldn't in a business environment.
Basically, it boils down to what you consider to be important. There's various opinions but it boils down to how you wish people to be able to use your code.
The BSD (and similar) licences are fairly permissive, they basically allow you to do what you like with the code so long as you retain the copyright/licensing notices. (ie, give credit where due), the argument for this kind of licensing is that it's rather pointless re-inventing the wheel, so why not make your stuff available. An example would be the BSD TCP stack, why rewrite a complex and error prone piece of software when there's one available for you to use and potentially improve. If you choose to give back your changes, that's all well and good, but not the main thrust or intent of the licence. This is the kind of licence used by people like Apple, a lot of OS X is based upon FreeBSD; quite legally, and in the spirit of the licence too.
The other side of the coin is the GPL style licensing. This is more about the freedom to understand and share the code behind your product. You're free to add and change the code to your hearts desire, however you must (in theory) make your changes available for all, so they can be inspected, reviewed and adopted by others; also it in theory prevents you from distributing software that can't be understood or examined as you have to make the source code available. This is the approach taken by Linux and other projects; although this intent has been subverted somewhat by larger companies. For example, Google don't release any of their internal system code as they don't distribute binaries, you just /use/ the software, or with Android they're moving more and more code into proprietary components so in effect having their cake and eating it too. It's this kind of behaviour Redis are attempting to address.
Most of the OS licences fall between these two ends of the spectrum, which you choose is as much about your views on the use of your software as it is with anything else.
If you want people to be able to use your source code, but you're not bothered if they make any changes public then the BSD/Apache licences are the way to go about it, otherwise the GPL and variants are probably where you should be looking.
And it's the internet, so whichever one you chose someone will probably tell you you're wrong. :)