The sci.electronics.* groups on Usenet are full of good people. I also like to look in on comp.arch.embedded and comp.arch.fpga and rec.radio.amateur.homebrew every now and then.
If you're at a university or your ISP does usenet, I recommend using an actual newsreader, but you can fall back on the google groups web interface
There's the occasional loon or asshole but that's what killfiles are for.