André Felipe Menezes has amassed a beautiful collection of posters, with a focus on graphics and typography, and is cataloging them in an online museum for everyone to view. It's sort of a wiki-style museum, as contributors, once invited or accepted, are tasked with organizing their own directory of posters. Simply amazing work. The site is described thus:

we intend to become a good resource of graphic and typographic posters to serve all your research needs – either historical or inspirational.

our ideal is simple: feed and consume quality.

although posters may contain illustrative and photographical content, we catalog only those with notable graphical or typographical quality.
just because we love the pure form of graphic design – shapes, types and colors.

typo/graphic posters is a invitation and application-only project. if you're not invited apply now, don't hesitate. just email team@typographicposters.com with your website and all posters attached, if approved, you'll receive a password and further instructions to manage your own directory.

Great work,  André.