I don't want to start linking examples (because that's pointing a finger) but there is a definitely a (small but enthusiastic) group of users here who routinely answer questions in the comments field. I don't mean one-liners, but substantial multi-line comments, making full use of the space available in a comment (or two).
Some SE sites are clearly against this practice, and some don't seem to care so much. Those who do oppose it tend to use the justification that answers in comments can't be downvoted, so that the normal community-feedback mechanisms cannot be applied to gauging the quality of the answer. Equally, the rep of the author is not raised by upvotes, so it's not so clear to people reading them that they're written by someone with a track record of good answers.
How do we feel about it?