I'm guessing this is actually the European Cosmetics Direction, which has been "in" a lot longer that this year, in fact from 11 March 2005.
The European Cosmetics Directive.
Durable cosmetics, those with a shelf life of at least 30 months, are in the majority. Even so, some consumers want to know how long an opened product can be kept.
A symbol introduced by the industry in conjunction with European Union guidelines recommends the length of time a product remains useable after opening. This period is referred to as the ‘period after opening’ (PAO). The period is given as a number of months and is marked with a letter ‘M’ under or within the ‘open jar’ symbol. When a PAO symbol is required this will appear on the product itself and on the outside packaging.
In practice, most cosmetic and personal care products are formulated to ensure that they are safe to use and have a shelf-life which far exceeds the normal time it would take to use all the product.