I kept rereading OP's comment and looking for the difference between Adblock and AdBlock. It wasn't until your comment that I noticed the capital B in Block.

Trademarks FTW. Great example of confusion in the marketplace.

I read through nearly the entire thread thinking that the Adblock mentioned had a capital B.

Coming soon: uAdblock Origin Plus+.

Upgrade to PRO Version for $29.99 a year.

Is that the one without ads?

Don't forget about Adblock Edge, AdBlock Lite, μ Adblock, and Ad Blockerr:

https://addons.mozilla.org/en-US/firefox/search/?q=adblock

Cripes, this is starting to sound like the old phone books. Coming soon: AAAAAAA+ AdBlock?

Adblock would not be a trademarkable name anyway. It's a generic term that describes what the product is.

Don't tell Microsoft! (Windows, Word, Surface, etc.) Or Apple! (Pages, Numbers, etc.)

You might have a point if those products had been called "Operating System", "Text Editor" and "Portable Computer With Touchscreen and Keyboard".

On a technicality (which is what trademark attorneys deal in), your point falls to the same fallacy. The product Adblock is an "Advertisement blocking engine" or the like. "Adblock" is a made-up word and therefore likely eligible for trademark. (Or it was before the namespace got polluted with all the variants.)

"made up word" is overly generous. It's the word "ad" followed by the word "block". "ad block" is a valid description of what it does, equivalent to "advertisement blocking". You only put the word "engine" in there to fake there being a difference. Microsoft wouldn't be able to get a trademark on "Operatingsystem".

"Microsoft Word" is the trademark, not "Word".

Or is it? If Microsoft has trademarked just "Word", it is very strange that they don't enforce it against these folks:

http://www.abiword.org/

especially in the light of how, some years ago, their lawyers swooped down like hawks on a Canadian named Mike Rowe who put up a "Mike Rowe Soft" consulting business and web site.

"AbiWord" is a single word, which may be a factor. They might have trouble if it were "Abi Word" or "Word by Abi" or even "Word". It's implausible that another entity could market a competitor of Word (or Windows) by naming it e.g. "Apple Word" or "Apple Windows". I'm going to bet that all the common permutations are trademarked by MSFT.

Also, I'm guessing Abi's limited reach is a factor. If Abi was suddenly taking a meaningful share of usage, they would probably get an angry lawyer letter.

I kind of figured that Adblock Pro was a fork, but this is ridiculous.

You do not need to have a trademark registered to have trademark rights: you only need to be able to show that people associate the name with your brand.

I had not idea either until now. Always learning something new on HN.

TM are not automatic (unlike copyright at least in USA since 1978 Copyright Act) and they are fairly expensive and require vigilance (more $$$) to keep valid.