[gravypod]

Probably trademarks and copyrights.

[wongarsu]

Copyright doesn't apply to names, and the only US trademark for "clippy" is for medical equipment (and thus doesn't apply here) [1]. There doesn't seem to be any EU trademark for "clippy"

1: http://tmsearch.uspto.gov/bin/showfield?f=toc&state=4805%3At...