Political newsgroups do exist in many places around the world. Visit DejaNews or Remarq to find groups of interest. While the web has democratized access to newsgroups, local groups tend have a limit audience at the local level. Few people with political power or influence use newsgroups. They are the best place to send unruly e-mail list members who can't swallow your two posts a day rule.
Newspapers tend to host the most active online discussions on local and regional issues.
Discussions tend to be in response to specific stories and the online space tends to function as a privatized discussion connected to the news outlet. Useful, but generally not a place for people to organize new efforts politically. Visit ForumOne for the best directory of web forums. Web forums also are used at a more local level for organizing and hosting online special events. Read some hosting advice from David Woolley .