This option is for sites that have users sharing content that has commercial value - such as photographers, artists, designers, etc. It provides the user the most rights and the site operator can only use the content in very limited ways related directly to the operation of the forum. This type of license is usually used with private or limited-access forums. (more…)
USER CONTENT LICENSE:
You grant [FORUM] and its users a non-exclusive, royalty-free, worldwide limited license to use,
store, display, reproduce, modify, perform, and translate your Content solely for the purposes
of operating, developing, providing, and using [FORUM]. This includes without limitation distributing
part or all of [FORUM] in any media formats through any media channels, except Content not
shared publicly ("private") will not be distributed outside [FORUM].
Following termination or deactivation of your account, or if you remove any User Content from
[FORUM], we may retain your User Content for a commercially reasonable period of time for
backup, archival, or audit purposes.
Translation: [Forum] operators may only use your contributions to run the site; i.e. display your content to other people - who can interact with it (quote it, edit it, etc.).
Before assuming that everyone should favor this license, consider that very few forums do this - and most of them are Private and/or aren’t indexed by Google. It’s surprisingly hard to get people’s permission to use anything when you have rules like this. (See the YOYOW entry on Wikipedia…)
The next option: The original poster and the public may republish contributions, is also surprisingly uncommon.