As a patent attorney, I am constantly aware of how important it is for inventors and companies to keep their inventions confidential until they have filed an intended patent application. The reason for this is simple: going public before filing a patent application may prevent your application from being granted, or may cause your granted patent to be invalid and unenforceable. 

Whilst confidentiality is something that is at the forefront of my mind, it is inevitably not always at the top of the agenda for inventors and their new inventions. In today's online world, it is so easy to write a post about your invention, or possibly even share a video of a prototype. Whilst this might represent an excellent marketing opportunity, do consider the patent implications. The basic rule is that you can't obtain valid patent protection for an invention that is already in the public domain. This means that posting online may severely limit your options if you later decide to seek patent protection to prevent others from freely copying your invention.

Of course, accidental public disclosures do happen before an application has been filed. Fortunately, such disclosures are not always a complete bar to patentability - this comes down to the details of the invention as compared to the details of what was actually disclosed. In these situations, do seek advice from a patent attorney. Nonetheless, avoiding public disclosures before filing your patent application is always preferable. This is perhaps best summarised by the wise old wizard, Gandalf: "Keep it secret. Keep it safe." (The Lord of the Rings: The Fellowship of the Rings)...