I've been a member of a number of religious groups. Whether parish, congregation, sangha, temple, cult, grove or Heathen Sunday School class, I actively seek out opportunities to compare notes with others about my spiritual and metaphysical experiences. I'm happy to be a member of a Unitarian Universalist congregation; I enjoy the support of other people, being part of something larger than myself, and working with others toward a common goal informed by our understanding of virtue and ethics.
What I have never found, aside from the companionable understanding of my spouse and my sister, are coreligionists. I have friends who have aspects of their practice that align with mine in many ways, but I have no group I can go to where their offerings, their powers, and their metaphors will be the same as mine. I made my peace with this back when I was doing Project Protagonist.
I can't help but feel like trying to find a single religious community that fulfills all of my needs is likely to end in trying to fit myself into the beliefs of the larger community. My faith and my religious experience and #mypolytheism are small scale; they exist within myself and my close family, within my mantra repetition and my offerings in the dark, within my spouse and I discussing theology at midnight while the baby sleeps, within my daughter waving and saying "thank you" at Mara's altar. #mypolytheism doesn't exist in a vacuum. It exists in a wider context, but it exists apart from that wider context.
Community exists outside of my specific beliefs and experiences of the spirits and powers, outside of my household and my family. My community is the UU church, not because CUUPS encompasses my beliefs (it doesn't particularly, and tends to have meetings I can't make it to besides), but because the people there have been welcoming and because I have different things in common with them.
My values and ethics come from my gods, but they are not unique to my gods. I sought out a community that embraced many of the same values I do, and my spouse and I decided the UU church and values were the best fit. They value family enough to provide childcare and religious education. UUs value spiritual exploration and questioning, social justice and compassion and dignity. We come together on Sunday mornings (and sometimes Friday nights, or Tuesdays, or Saturday afternoons...) because we believe in trying to create a community based on those values. The UU church strengthens my understanding of how faith and the world interact, and in return my gods send me back to the church. (Redbird's really excited about me teaching OWL this year, let me tell you.)
My polytheist community is on The Cauldron and Facebook and, yes, Tumblr, in pockets of people and Skype chats and IRC, places where I feel comfortable talking about what I'm working on and getting feedback. I enjoy these kinds of places precisely because everyone there has a different background, different deities, different ways of acting on what we know about magic and religion. What each group gives is a common language, a context in which we can discuss various techniques and experiences so that others are more likely to understand what we're talking about and coach their advice or encouragement in the same language.
Online community has other benefits, as Estara T'Shirai outlined in the post that planted the seed for this one. Facebook and message boards fit into my busy schedule, allowing me more time to discuss the gods than I'm able to carve out for coffee shop salons or pagan store classes. I missed so many meetups and rituals when I was working two retail-sector jobs, but I could always find a space online to talk about offerings or rituals or what I was reading.
In a related vein, #mypolytheism offers a language and a time in which to have a conversation. Unitarian Universalism offers me people to have a conversation with. Maybe none of these people believe the exact same things as me, or work with the same powers and spirits. Who cares? Not me, not them. Neither did most of the the druids or the heathens or any of the explicitly pagan groups I've attended. Having my own beliefs, interacting with #mypolytheism, doesn't stop my from interacting with communities both online and face to face. They're simply two related, but separate, concepts.