Today, The Internet Archive launched
The Internet Arcade, a free, emulated, browser-compatible collection comprising arcade games from the 1970s to the 1990s.
Of course, while some games in the archive have been effectively abandoned and even forgotten, others are still popular and actively exploited by their creators, such as games in the Pac-Man
franchise. Games from well-known companies such as Capcom, Konami, Namco, Taito, and Sega appear in the list, among many others -- around 900, in total.
Archivist Jason Scott writes about
the process of getting the Arcade up and running on his personal blog. He explains its purpose like this: "... my hope is that a handful, a probably tiny percentage [of players], will begin plotting out ways to use this stuff in research, in writing, and remixing these old games into understanding their contexts."
[UPDATE: Commenters note that the legality of the effort is unclear - the Internet Archive is a non-profit, but it does not appear that they have attempted to contact IP holders before making these titles available.]
The Internet Archive preserves webpage content so that it remains publicly available even after it has disappeared from the live web. You can find out more
about the Archive, and read its copyright terms here