I'm the editor of Grove. First, thanks for checking it out and for talking about it here. Our initial goal was to create some compelling pieces that the entrepreneur community would find helpful. To that end, we took the advice we got from the founders we worked with to build the site, which is launch and improve over time. The ability to comment is certainly one of the things we'd like to add going forward, but we feel we have to earn the right to be a community site first. We're hosting a drinkup next month, which hopefully will be a start. In the meantime, forums like HN where there is already a big community are a great place to discuss the site.
FYI here's a link to the drinkup: https://sequoia.co1.qualtrics.com/SE/?SID=SV_dpzD7CVJ0DtTwgd