The data visualization community needs its own Hacker News
medium.com
medium.com
There generally isn't too much commenting going on though, despite generating a decent number of views. This makes sense - I only give feedback to a small percentage of things I see on the internet. I would like to interact with other designers more, but sending unsolicited comments/criticism via a tweet or an email doesn't seem appropriate most of the time.
I included a small note on the bottom of my last project "Have an idea for another graphic? Think I did something wrong? Hit me up! adam.r.pearce@gmail.com | @adamrpearce" which resulted in a couple of interesting email threads. None of those conversations really need to be private though.
When I make a new project, I'm lucky enough to have a small group of people who are in the business who I can trust to give me feedback. But I've spent years cultivating that group, and it's not really fair to newcomers who want feedback on their first work, or just want to lurk and listen to the experts debate things (which is what I usually do on HN). That's all private or hard-to-find now, which is a problem.
/r/d3js , /r/visualization , /r/Infographics
schema.org/ > Thing > CreativeWork > { Article, Dataset, DataCatalog, MediaObject, and CollectionPage } may also be helpful.