Bulletin board
（重定向自Pinboard）
A bulletin board (pinboard, pin board, noticeboard, or notice board in British English) is a surface intended for the posting of public messages, for example, to advertise items wanted or for sale, announce events, or provide information. Bulletin boards are often made of a material such as cork to facilitate addition and removal of messages, or they can be placed on computer networks so people can leave and erase messages for other people to read and see.