If you want to gen up on classic Porsche then check out these blogs:
http://www.ferdinandmagazine.com/classic-porsche-blog. Established in 2006 as John Glynn's Classic Porsche Blog ,this fascinating site contains over 1000 Porsche articles.
For more general Porsche info, have a look at http://flatsixes.com/, set up by a husband and wife team, who are Porsche fanatics.
If you want to join a forum there are a whole host to choose from, depending on your interest...
For classic Porsche fans http://www.ddk-online.com/ is very highly esteemed "We welcome owners or enthusiasts of 356, 911 (pre 73), 912, 914 and all Replicas"
For early 911S models there is http://www.early911sregistry.org/ , a membership based forum which also provides a quarterly publication and a registry of owners and vehicle information.
There is also http://www.911uk.com/ which (surprisingly!) focuses on all things Porsche 911.
https://www.impactbumpers.com/ is a Porsche 911 forum hosted by Ferdinand: The Cult of Porsche Magazine (mentioned above)
Porsche Club Members can enjoy a chat forum about all models of Porsche. https://www.porscheclubgb.com/forum/