There are substantial benefits to marking a product as patented.  

Done properly, patent marking provides "constructive notice" of patent rights to a potential infringer and starts the period during which patent damages may be recovered from an infringer.  

Prior to passage of the America Invents Act in September 2011, proper patent marking entailed placing the patent numbers covering the product directly on the product. 

The disadvantages of this process included the cost of placing all pertinent patent numbers on a patented product, and the inconvenience and expense of revising product patent marking when new patents issue or older patents expire.  "Virtual" patent marking permitted by the new law enables manufacturers to take advantage of the constructive notice afforded by patent marking while substantially reducing the disadvantages.

In its simplest form,virtual patent marking consists of placing the word "Patent" or the abbreviation"Pat." on the patented product along with a freely accessible Internet address where the specific patents associated with each patented product are listed. 

Such a system permits the patent owner to easily update the website to add new patents, delete expired patents,or modify the website if a patented product is re-engineered to include more or less patented features.

The new law does not change the requirement to mark the actual product with "Patent" or "Pat."  When it is possible to put a notice on the product, merely putting the notice in advertising, instructions or on packaging will not suffice to obtain the benefits of patent marking.