To avoid damaging your patent rights, mark your products with patent numbers. The law (35 USC 287) covers devices but not methods, so marking software is a bit tricky.
You probably have noticed that some products are marked with the word “patent” and a list of patent numbers. These are usually written in small type somewhere on the product or on its packaging. If you (as a patent holder) are planning to start producing your own patented products, what happens if you don’t include this marking?
Because it is hard to tell what is and isn’t patented, Congress passed the 35 USC 287 statute (Federal law) to protect the public from accidental patent infringement. The law holds that absent such marking, your ability to recover past damages from an infringer can be very limited. For example, past damages may only extend back to the time that (presumably after suitable claim chart analysis) you first sent a notice letter to the infringer. This law also covers your patent licensees (who often forget such markings) as well, so remember this for license negotiations. Otherwise, your licensee could end up damaging your rights.
Although traditionally actual patent numbers had to be marked on the product, a few years ago it became OK to just use “virtual marking”. Here, just marking “patent or pat”, followed by a publically accessible web page address, is enough. Virtual marking has advantages, but make sure the web page is actually “up”.
To prevent inadvertent loss of rights, it may seem safer to always err on the side of marking, but don’t overdo it. There is a different law, 35 USC 292, designed to protect the public against false patent marking. So the general rule of thumb is to try to provide adequate patent notice, but avoid being deceptive.
35 USC 287 has some “bugs” and “features”
Bugs: Untended consequence — the law somewhat favors patent trolls. A patent holder who doesn’t produce anything (and hence has nothing to mark) can still recover past damages from up to six years earlier.
Features: Because it is hard to affix a mark to a method, 35 USC 287 generally doesn’t apply to methods patents.
But what about software and software implemented inventions? Software patents often contain a mixture of methods claims and device claims. However, software typically runs on (or is stored in) some sort of physical object. So is software covered by 35 USC 287 or not? If so, what to mark, and how to mark it? What about websites and apps?
The courts have not been consistent here, and the law is still evolving. However, a fair number of court cases have required marking. It is safest to assume that patent marking is likely required, and then examine legal aspects as they apply to the specifics of your situation.