When I've participated in a song in the Songs forum I primarily share it for exposure.
Secondarily, critiques on the mix is considered (even if not applied) if I did the production.
Finally if is an original piece then thoughts on song structure, lyric or melody is welcomed (even if not applied).
Since I feel that songs I participate in fall into two classes;
1. Collaboration with serious intent
2. Collaboration with full buffonery in mind
On # 1 it's nice to hear if performances were well met by the listener. But given that we are recording and not producing a "live" performance, that's less of a concern to me because I cannot tell you if the collaborators played their parts in one take or comped it all.
On #2 it's all about the buffonery, and if that works for at least one person, the job is complete IMO.