The particular method is frowned upon (because it could be faked), but the reasoning behind it is sound: As long as you can prove that you had an idea on such-a

The particular method is frowned upon (because it could be faked), but the reasoning behind it is sound: As long as you can prove that you had an idea on such-and-such a date, you can challenge any later patent on it, and file for a patent yourself at any time (or rather, until other folks start using your idea without you challenging them). Think of some electronic equivalents of sending yourself certified mail: save your idea on Google Docs; email it to yourself and your friends; check it into a private Github repo and save it to Tarsnap (both cost $$ unless you're already using those services). You should flesh out your idea in great detail, as detailed as a patent. If you take all these steps, you should be able to successfully challenge any later patent on the idea. But, if you want to be able to sue anyone who uses your idea, you're going to need a patent. That's what a patent is: a license to sue. So if there's a good chance that someone will use your idea in the next few years, filing for a patent now will save you a lot of headaches. Remember that it takes years for a patent to be approved.