I think you might be best looking for some kind of dictionary of marketing terms - I would think that such a book exists. Jargon is used so much in marketing and it is very fast moving.

-in Italian there is only one word for president and chairman: can anyone explain the difference?
I think it is just a regional variation. In the UK a company's board would be lead by its chairman. In the USA I think president is used more often (maybe because it has more status, it also has the benefit of not being gender specific). I'm willing to be corrected on this.

-…”industry best-practices information.”
This is just jargon for finding put what is the norm in a given field/what works best.

- addressable
Perhaps it means the kind of leaflet or piece which leaves a space for the address so it can be sent out easily - you will probably have to look at context.

- ‘print fulfillment’
Just jargon for the whole process of producing print (posters, leaflets, direct mail letters) and, more importantly making sure they are distributed (direct mail, leaflet distribution)

- A whole sentence now: “Playgrounds are like the proverbial camels, known in the old joke as ‘horses designed by committee.’
Perhaps because the Italian government (as an example of a committee) rarely lasts long enough to design a camel (joke??). The image is of a committee setting out to design a horse. Because committees are better at incorporating everyone's ideas than cutting out ideas the final product is a camel rather than a horse. You'd have to look at the context to work out why this applies to a playground, perhaps there are lots if separate things to do but it doesn't work together as a whole.

Hope this is useful.