I am a huge Spyderco fan. A Gen 4 Endura ZDP-189 is my lone EDC. There is no rotation unless one counts a Gen 4 Endura VG-10 or a Pacific Salt that I ocassionally sub in. Go see the "For Sale" forum. Last month I sold off my last two BM 806D2s because I like the ZDP Endura that much better.
All that said, I respectfully disagree with the trademarking of the hole. IMO, Spyderco's trademark should be considered the bug.
It is beyond obvious that Spyderco had a patent on the hole. They benefitted from a set market monopoly for having innovated it and defending it.
It is a rather simple tenet of trademark law that a trademark cannot cover a functional product improvement. It is especially quirky to trademark a formerly patent protected feature.
I have seen all of the arguments, "but people can use different shaped holes," and "all automobiles have grills, but no one disputes BMWs 'kidney shaped' inlets." I remain unconvinced.
The easiest hole to make is still a circular one. It was and remains marketed as a competitive advantage, though some market identity language has been layered on in the past few years. That the hole has only recently made its appearance on Spyderco's fixed blades after over two decades of being on folders also undermines the trademark argument.
Here is how the hole is described in Spyderco's 2007 Product Guide:
SPYDERCO TRADEMARK ROUND HOLE
The Spyderco Trademark Round Hole is the industry symbol of quality. It is our most recognizeable feature and facilitates easy opening and closing of our knives with one hand. The hole offers convenient access and maximum control as well as accommodating large, small, and gloved hands. The position of the hole in the blade and the fact that it is round allow for a continuous opening motion. The thumb rests against the hole at a comfortable distance from the the palm permitting easy rotation from the pivot point.
To open the knife using the hole, place the knife in your open hand at the base of your fingers and grasp the clip side of the handle with the tips of your fingers. Rest the pad of your thumb in the hole and then gently and smoothly slide the blade away from the handle. When a solid click is heard, the knife is locked into an open position (note that the blade should always be locked securely in the full open position before use).
One sentence about it being a recognition feature. Nearly two full paragraphs describing it as a unique feature for a folder. Nothing about why the hole is on the later fixed blade models or of what possible use it might be on a fixed blade.
I understand the intent is now to expand the use of the hole across the entire product line where practical. However, that makes for a weak trademark defense, again IMO. It is arguable that Knives of Alaska has just as long a pedigree of using holes in the aft portion of a fixed blade below the spine as Spyderco does, which only just started doing this themselves.
One of the tests of trademark law is about market dress and the potential for confusing the prospective customer as to the identity of the true maker holding the trademark. It is under such legal guidance that permits BMW to trademark its grill shape, but then again, BMW aggressively defends the trademark and does not "license" it to other competition. Coke retains its bottle shape protection because the bottle conveys consumer information, not because Coke claims that the bottle is superior, even implictly, in its marketing. Coke also aggressively defends the unique appearance of its glass bottled product line.
Now imagine a world wherein Coca-Cola had invented the current aluminum pop up tab rather than using the old school pull tab. Say that they enjoyed a monopoly period, but began licensing the tab to beer companies and even minor players in the cola market like RC Cola.
How absurd would it be today to call that tab its most recognizeable trademark of quality, which supposedly sets it apart in the industry and to at the same time argue that it is the most functional, all the while licensing it out to direct competitors? It wouldn't add up in the beverage industry, but it somehow makes total sense to some in the cutlery business.
I am still waiting for someone to demonstrate in any other business an example of one competitor licensing out its "industry symbol of quality" to other makers of similar products. We are not talking about Smith and Wesson branding "lifestyle" products, or Jack Daniels pimping barbeque sauce, we're talking about a situation analogous to Nike licensing their trademarked Swoosh to Reebok or Adidas for a line of shoes.
If it doesn't add up to have a swooshed Adidas, it doesn't add up any better to "license" a circular holed Brand X knife with Spyderco's blessing unless the math is that defending the trademark is too difficult to be cost effective and might even be lost.
That last bit is where I think the truth of the matter resides. Some companies defend their trademarkings to the last breath because the only way to ensure an enduring trademark is to litigate it with infringers when they appear.
Just try and market lingere under the name Vicky's Mystery in the same market as a Victoria's Secret, advertise in the local paper, and see how long it takes to get the first Cease and Desist letter from VS's corporate attorneys. There will not be a licensing deal waiting in the wings--ever.