SodaHead, a community site for the debate of serious topics, has raised an $8.4 million second round led by Mission Ventures, along with past backer Mohr Davidow. The Santa Clara, CA-based company raised $4.25 million back in 2006, bringing its total raise to $12.65 million. SodaHead was started by ex-MySpace exec Jason Feffer, and it hopes to be the internet’s “town square”, where people throw in their two cents on stuff like politics. The site seems pretty active, at least judging by the comments thread on whether Obama should pick Clinton to be his running mate. Funding will go to new marketing initiatives and new hires. Release.