This site isn't only focused on tech, there's also a lot of tech entrepreneurship - particularly the VC-funded Bay Area variety, and also a bit of gossip about that community.

For tech, https://lobste.rs is decent. There's more interest in papers and proofs-of-concept than here. (Give a link to your profile on Twitter/GitHub/here in #lobsters on Freenode and someone will give an invite pretty quickly.)

For bootstrapped entrepreneurship, https://barnacl.es (my site) is small but welcoming and growing. (No invite needed.)