The difference being, coloring fiberglass insulation serves to identify its brand, and serves no other purpose.
Red soled shoes are arguably better looking, which is a functional purpose of shoes. So you shouldn't be able to trademark them. Trademarks should only prevent people passing off goods as yours, not copying your function.
Similarly, Apple shouldn't be able to trademark Aluminium notebooks, or single button phones, as they have a functional purpose.
Of course, their is a question as to whether aesthetics is a function, and whether restrictions on aesthetics will limit the function of competitors' offerings. In fiberglass insulation, I doubt it. High-heels, maybe.
I'd have argued that the red soles were indeed intended to be for identification only. Anything else is a function of people's perceptions (e.g. beauty is in the eye of the beholder.)
Lest we argue that red soles are aesthetically functional as well, regardless of the designer's intent, let's consider the possible repercussions of pink insulation when applied inside transparent walls. Or perhaps the calming effect the color has on installers. Now, the pink is functional. Does that make it less able to be protected?
I really think it goes back to the intent of the creator/designer/architect of the product. The designer of the shoes seems to have argued the aesthetic qualities of the color on the sole and therefore nullified his ability to claim the use of color was not "functional." If he'd held out with the argument that his intent was identity, he may have won.
I read the article. And then I commented, providing information NOT PROVIDED IN THE ARTICLE. Namely, a correct legal citation to one of the most famous color trademark cases, and a link to the court's decision.
edit: could the down voters please explain yourselves? Am I wrong in assuming that some people would like to read the actual case mentioned in the article, instead of just a couple sentences about it?
When contributing value to the discussion, context is important. The article clearly distinguishes this situation from the case you cited. If you want to discuss that decision in more detail, try:
"If anyone is interested in the case mentioned in the article, here is a link to the full-text decision. [link]
Because the colour used in that trade mark was purely for the purpose of identifying the product and had no practical or aesthetic purpose, the court held that the colour could not be used by competitors."
