Not that I know of.
Some people (like me) may object to the notion of "see who is subscribed to a thread" as a potential Big Brother issue, and/or the potential of stalking or counter-stalking by individuals and companies. That being said, companies like Google, Facebook, Amazon, etc.or organizations like NSA may know anyways because of the breadcrumb trails people leave by visiting pages.
In case you think I'm paranoid, watch the documentaries "Citizen Four" and "Zero Days."
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]