Every has these terms
A browser like Chrome may not need or want this language, but i see thousands of web sites with forums, bulletin boards, and user generated content, that all have this language. It is common.
As examples from big brand names on either side of the Atlantic, check the Nike and BBC T&C's regarding user generated content.
Oh, and lets check Apple
http://discussions.apple.com/help.jspa
License to Use Submission. By sending a Submission to the Site you agree to grant Apple a perpetual, royalty-free, non-exclusive worldwide right and license to use, reproduce, modify, adapt, publish, translate, create derivative works from, distribute, perform, play, make available to the public, and exercise all copyright and publicity rights with respect to the Submission. If you do not want to grant to Apple the rights set out above, do not send your Submission to the Site.
And Microsoft
http://www.microsoft.com/info/cpyright.mspx#E3D
However, by posting, uploading, inputting, providing or submitting ("Posting") your Submission you are granting Microsoft, its affiliated companies and necessary sublicensees permission to use your Submission in connection with the operation of their Internet businesses (including, without limitation, all Microsoft Services), including, without limitation, the license rights to: copy, distribute, transmit, publicly display, publicly perform, reproduce, edit, translate and reformat your Submission; to publish your name in connection with your Submission; and the right to sublicense such rights to any supplier of the Services.
If you don't like it then don't post.