I think that kind of the idea with http://barnacl.es/, it's more about people trying to bootstrap and/or run a lifestyle business, but I'd say that overlaps with the 'side-project that makes money' crowd pretty well.
I have been reading it for the past few months, the traffic is pretty low and it's a bit marketing guide heavy at times, but overall an interesting community IMHO.
is one - for sharing ideas and getting feedback. I've read a few interesting threads and advice and results there. Also, their site design and appearance are interesting (though a side point).
I guess ProductHunt too, though haven't checked that a lot (yet).
I find the entrepreneur subreddit to be pretty terrible, honestly. My biggest problem is that to the less experienced, reading it can give you a false sense of being productive. Many years ago, I was reading it constantly because I was convinced one day I would find the secret to having a successful business.
However, it's overwhelmingly filled with people who have pretty low ambitions. It's mostly projects that are better suited for an etsy store than they are as a stand-alone startup. The ones with more ambition are usually something like "Uber for dogs" or "Facebook for dogs" and lack any real possibility of ever becoming a meaningful product.
I totally agree, but occasionally there are posts that are worthwhile. Some people have done great write ups about how they've scaled their small businesses to a point where they make a living, but like I said... have to weed through a lot of junk to see something good.
I have been reading it for the past few months, the traffic is pretty low and it's a bit marketing guide heavy at times, but overall an interesting community IMHO.