Since I've become a dad, I've sought camaraderie within a number of organizations and groups that cater to dads.
I also belong to a number of mom communities, and general parenting communities as well, but the dad ones speak a little more to me, have helped me find my Tribe of Dads
Here's a list of just some of the Dad Communities I belong to:
City Dads Group http://www.citydadsgroup.com
When I was a newbie father, I discovered a cool meetup group that had started a few months before I became a dad-- the NYC Dads Group. Founded by Lance Somerfeld (and the quickly joined by his partner Matt Schneider) the NYC Dads Group went from about 100 dads when I joined to a 22 city network of dads that number in the thousands.
When I lived in NY I was very involved in the organization (I was one of the first co-hosts of its podcast The Modern Dads Podcast, and I still occasionally contribute) I was the cultural coordinator, so organized a few meetups, and as well I was a pretty frequent contributor to their blog.
Since I've moved to Chicago, I've become involved in the local chapter Chicago Dad's Group, and write for their blog (local and national) and also do some cultural coordination. Of course, my son is older now, and my need for hooking up with other dads has lessened a little bit. It's still a great organization, and I think an essential group to belong to if you are an involved dad or a primary caregiver, especially a newbie. Although it's organized online, the heart of the group is face to face meetups.
Dad 2.0 Summit http://www.dad2summit.com
Life Of Dad http://www.lifeofdad.com
Dad Blogger's Facebook Group https://www.facebook.com/groups/dadbloggers/
Blogger Father), this group has grown to over 1000 guys all who have blogs. It's a closed group, meaning you have to be approved, and primarily to do that, go to the site, and send a message, with a link to your blog. The basic rules of the conference are to not be a dick, and for the most part, that works. There are share threads (threads where you can share your blog posts) and lots of helpful people. It can get a little raucous, and occasionally a little dick-jokey, but it's one of the best ways to meet a whole bunch of dad bloggers all at once.
National At-Home Dad Network http://athomedad.org/
Hamilton.) I know a lot of the organizers, and they are smart, compassionate, and very eager to help. If you are an At-Home Dad, I can highly recommend this group.
These are great resources to start with if you are a dad looking for your tribe.
Please list links to your community(ies) in the comments!