From PC Magazine:
The Copyright Office within the LOC on Monday ruled that jailbreaking a smartphone – particularly Apple’s iPhone – is permissible under the Digital Millennium Copyright Act’s (DMCA) fair use provisions.
From Search Engine Watch:
[The Copyright Office also] granted an exemption for people remixing videos on YouTube, declaring it is not a violation of DMCA if they use excerpts from DVDs for the purpose of criticism or comment.
Read the decisions for more information.