After reading the insightful Flattery post from Sacha Greif, I thought some clarification was needed.
It’s all in the intent, both for the author and the user.
There is an important difference between Style and Identity.
A style is a general concept, grouping “families” of brands and Identities.
There is indeed an “Apple Style”.
Apple has contributed to it, but not only. One can think Metalab has a part in it, and so have thousands of mac developers, and designers. Apple encourages the community to build on this style, expand and distribute it.
More generally, a style is a collective work drawing from a general pool of ideas, user interface elements (in the case of software) and layouts coming together.
So you have an Helvetica Style, a Flat UI style, an Apple Style…
Then there is the Identity
Drawing from a style, or defining a new one in rare cases, an Identity has a well defined Color palette, Button treatment (such as a specific rounding radius, padding), illustration style, Type choice with specific font sizes and kerning.
It recognizes the uniqueness, the personality of a brand, and usually, they don’t want this copied or exploited.
Apple, is very relaxed about people copying their style, because they know it’ll reinforce their Identity.
Indeed, they decided that their uniqueness is not their in their software UI, but their products.
As for Kickoff, I do agree with Sacha that the general style draws very heavily on the Apple Style, but it does not completely steal their Identity : Although close, you definitely could not find this kind of page treatment anywhere at Apple
It’s all in the Intent.
From the Brand’s perspective, this Identity very much has value : it’s what sets them apart from the competition, makes them instantly recognizable from the huge crowd of other services available, and establish a unique tone.
Don’t take this the wrong way : It’s not their differenciator, hopefully. But it’s the best way for them to stand out. Imagine if all your friends had the same faces. Would they like that ? Would you like that ?
As for the Layervault vs Designmodo situation, or the WP-svbtle theme, that’s and Identity we’re talking about : The clear goal is to generate money by diluting the uniqueness the brand has worked hard to establish. And in this case, Layervault was not OK with it.
I think the real value is not the intellectual property, but the uniqueness you get by defining an identity. If the author decides that it’s OK to copy, then fine, go ahead.
But if he does not, he can have valid reasons and it’d be nice if you respected his preference.