The public disclosure of a new idea stops others from patenting it. However, a patent application must be applied for within a year of the public disclosure.
Dave, I'd say you are wrong here. Only the first part is correct.
The public disclosure of a new idea stops others from patenting it.
Second part - once an idea is
publically disclosed but without an issued Patent or application, you've no chance of stopping anyone, worldwide, from using the idea.