I notice that one of the top stories on ElReg today is illustrated with a Microsoft logo - could that be infringment? Could Microsoft ask you to remove it? I am assuming that you don't pay Microsoft to use it?

...to me it looks like Avis disagree with the blogger's position on these car rental liability laws, and having no excuse to just ask him to take down the whole post, they show their annoyance by insisting he remove their logo.

I noticed you used our UK Stop Sign logo in your comment. Please refrain from using this copyrighted logo and remove it instantly from your comment about logo copyright infringments on the popular IT news site The Register (TM)

presumably if he went to a car rental site and took a photo of their logo on the building he could post that as much wanted as he owns the picture. Or maybe he could even photograph a monitor showing their website and crop it around the logo? Does copyright extend to that?

Actually, you're wrong - although in English, the octagonal red "STOP" sign is in wide use across Europe, and is not solely a UK symbol. Therefore I'm quite sure it isn't applicable to UK copyright, and anyway, being a public road sign, I'm not sure it's applicable to any copyright at all..

Photos of copyright content are complex. Wikicommons has some good (US-centric) advice and categorisation for how to work around it.

As an example of just how perverse it can get:

http://en.wikipedia.org/wiki/Image:Waterboard3-small.jpg

The wikipedians falling over themselves to correctly observe copyright on a photo of a Khmer Rouge torture manual

"Understandably, trademark law is not within your area of expertise. Therefore, we trust that this was done out of IGNORANCE and not based on an intent to misuse our mark to the benefit of your personal injury practice. We ask that you remove it immediately and refrain from any similar use in the future."

In the above quoted paragraph, the Avis lawyer uses the word ignorance in a way that could/would piss off most anyone. I'm sure that there are other words that would make Avis point without calling the blogger ignorant, i.e., sugar trumps being pissed off.....

When I was at Uni (Loughborough), our printing room had a policy that they would not print any photographic material which had the logo of any company in it. So if you took a photo of someone you were interviewing on the High Street for a project and there was a McDonalds logo somewhere in the background, forget about it. They even had examples of unsuitable photos posted up.