Wincustomize.com has adopted a policy whereby many works such as the Simpsons can be accepted under the terms of 'fair use'/'fan art'.  The administration has often mused at the apparent absurdity of being able to obtain [for example] a Simpsons Logon at other sites but not at their own.  Why this conflicting 'stance'?

Our policy is that the works be 'value added' and not just the reposting of a proprietary wall as a wall, for example, but if incorporated within a logon with appropriate additional input then it would be OK.

If and when [in that case] Matt Groening and/or Fox or an agent thereof requested their removal it would be accommodated without argument and universally applied to any/all related works.

To date, the only 'corporations' who have ever expressed specific displeasure/refusal have been the American Football codes [NFL] and Apple.

In an 'ideal world' exactly nothing would be accepted unless 100% consentual or original....but next time you are planning pedantry, think about all those incidentals mostly forgotten/ignored....OS icons, fonts, etc.  It's never 'simple'.

One way or another a line has to be drawn in the sand.....and as many people as possible need to be reasonably happy with that line.

Those who are not, for whatever reason, can find their own beach and start making squiggles...