Of course comments are copyrighted, if they happen to contain text that is novel. As an example, in the reddit TOS, they require commenters to license their comments to reddit.
> If so, do you feel the same way about opinions you share out in a supermarket or on the street?
Well being novel isn't the only criteria for copyright, the work must also be "fixated", and opinions in a supermarket usually isn't (but they can be, if I film them and post on reels or something; then the video itself is copyrighted)
> To meet the fixation requirement, a work of authorship must be fixed in a tangible medium of expression. Protection attaches automatically to an eligible work the moment the work is fixed. A work is considered to be fixed so long as it is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration.
> If so, do you feel the same way about opinions you share out in a supermarket or on the street?
Well being novel isn't the only criteria for copyright, the work must also be "fixated", and opinions in a supermarket usually isn't (but they can be, if I film them and post on reels or something; then the video itself is copyrighted)
https://copyrightalliance.org/education/copyright-law-explai...
> Fixation
> To meet the fixation requirement, a work of authorship must be fixed in a tangible medium of expression. Protection attaches automatically to an eligible work the moment the work is fixed. A work is considered to be fixed so long as it is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration.