I've started a local history community for anyone interested: seattlehistory. I figure there have to be a lot of folks here interested in the topic, from you proud Seattle natives to us more recent arrivals ... not to mention a lot of kids in classes that would like to have a historically-oriented community to bounce ideas off of.
If you're interested, go ahead and join, and feel free to post about any research into local history you're doing or any help you want from other folks. Posting historical images is also tres cool. Family histories are great too! It's all about learning and sharing, so go check it out.