Even if it's just posted to scraps, I'd love to see sketches and lineart pieces. This may just be a personal preference, but to me, I almost prefer looking at sketches and lineart pieces to the finished picture. Sketches and lineart hold a lot of value to me as a developing artist because I get more of a feel of how the better artist (you) developed the drawing.
Hmm. Wow. A question best answered usually by the one who asks it. . Posting all the while may make an artist look active but are they actually putting their all into all those drawings that thhey do? But then again, posting after you make sure your art is Perfect.... thats gonna take some time and one finds that one is never truly sattisfied. If so what then? Don't post?
Follow what you feel is right. There is no right or wrong and truly there is no Obligation to do whichever. Quote ToLoveTwentyNine ; "Creativity is something that works differently for every person. I say, let the artist do whatever they need to do to keep that fragile balance healthy.I feel that an aritst should be free to post whatever they consider to be of worth to them here, dispite what the public ask for." Unquote.