Bitcoin does not necessarily need advertisment because when something is too good it can't be hidden, it is a choice to either invest in Bitcoin or not, advertising Bitcoin now is not something to be bothered about because it has pass that stage and has gotten the recognition needed . Investing in Bitcoin should become more of self convinction and not because it is what every body is doing or talking about, who will invest will invest and who will not invest will not invest irrespective of how much discussion and adverts.
Bitcoin is decentralized in nature which suggest that there is no central body or a marketing team that is responsible for doing any form of advertisement but we can't say that there had not been some sort of indirect advertisement that has made Bitcoin what it is now.
Bitcoin has enjoyed advertisement from us that are the primary users, from companies that has Bitcoin as one of their payment medium, most ads and betting sites that accepts Bitcoin also promote Bitcoin indirectly and so we can't say Bitcoin is too popular to be advertised. Bitcoin can't advertise itself but investors and people like us that knows it worth and the numerous advantages involved in investing in Bitcoin are the ones advertising Bitcoin.