As you noted, the US is different. I’m not sure what you mean exactly by “revealing” your idea, but in the US, at least, I’ll provide a counter-example. (I forgot my UK and Japan law as it has been 6 years since I’ve done any real patent work). In the US, you are allowed to go to market for one year (the timeliness requirement needed to avoid a statutory bar to your patent application found in 35 U.S.C. § 102(b) of the patent code). Among the other reasons for allowing this year (focusing on benefits for the patent holder) time frame allows: testing of marketability of the invention to justify the patent cost; allows time for peer review as it conforms to society’s view of science and expectations; and, gives the inventor time to review and reflect on his invention, and give thought to other requirements to meet in § 102 (ex., like the “best practices” requirement). So, in my example, a potential patent filer can put his invention in market, thus exposing his idea, to see if his invention is worth filing. In the US, depending on other minute circumstances, if the filer A and B both conceive of the idea on the same day, but A reduces his invention to practice before B, but B files first, A will get the patent. (There are other scenarios and they play out with more complexity; I chose this one because it’s the easiest to illustrate). This is not true outside of the US. Whoever files first, given the other statutory requirements are met, will receive the patent.
Again, the US. is counter to the rest of the world: One can still disclose the information as long as it isn’t reduced to practice, generally speaking, as the § 102(a) requirement more often refers to reduction to practice for meeting the requirement of being “publicly known.” If A reduces to practice first, that will count as prior art (102(a)), but does not automatically bar the patent grant to B. B can still receive the patent if he can show that a) conceived of the idea first; and b) can show continuous dilligence with regards to the invention prior to A’s conception.
Last I checked, it was $685 just to issue the patent. There are all sorts of other filing fees and drawing fees and maintenance fees associated with it. To actually get a patent issued, contact a lawyer and the average market rate 6 years ago among large law firms was $10k (all attorneys fees included).
ascenray’s earlier post gave you a very good, simple distinction between patents and copyrights. There is a lot of subtlety, however, that is too difficult (at least for me anyways) to convey on a message board without requiring a huge thread.