Millions of kids are visiting and communicating in online sites and communities. While some concerns have been raised unsupervised and potentially harmful communication, a number of studies have identified great potential in kids' online talk, especially when related to feedback on user-generated content. Yet little research has been done at scale to show whether or not positive communication practices are broadly engaged in or supported online. This paper focuses on the informal peer support present in the online Scratch community, a youth programming site. Drawing on a random sample of 8,000 comments from over 5,000 random participants on the Scratch website gathered from January to March 2012, our analysis focuses on the quality of comments about projects and identifies their constructive, emotional and functional foci In the discussion, we address what these findings tell us about productive participation, potential for future research, and opportunities for scaffolding broader and richer participation.