I apologize for the shameless plug, but we're at the early stages of solving some of the problems you mentioned at http://NowVia.com
It lets you create topic-based "channels" that people can follow. So you could have one for 3-D printing, and when you add to it, you know everyone following it is specifically interested in 3-D printing. I'd love your feedback if you decide to have a play :-)
It lets you create topic-based "channels" that people can follow. So you could have one for 3-D printing, and when you add to it, you know everyone following it is specifically interested in 3-D printing. I'd love your feedback if you decide to have a play :-)