Poster is any piece of printed paper, designed to be attached on a wall or any other vertical surface. Generally, posters include text and graphic elements, although a poster may be completely graphic or textual.
The plaque is an advertisement written or printed on a sheet of paper and glued or hanged in public place. The format of the plaque allows the use of letters large enough to be seen from a decent distance. Besides the text, the poster may also contain artistic elements, conceptualized and constructed so as to attract the attention of those which addresses, and with the visual component not just to assist and supplement the perception of content, but also directly or associatively act over the sensibility of the recipient of the message.