At risk of being labeled an echochamberist, I'm going to agree that danah has a good point in her post about echo chambers. (See David Weinberger's article for more background.) I think it is natural to communicate most with people whom you share context and I believe that if you separate strong ties and weak ties a la Granovetter's Strength of Weak Ties, there is definitely a lot of "strong tie" hang-out-with-your-friends action that goes on on blogs. I think that's natural. Most blogs are conversations between a small group of friends.
It's clear that it's fun and easy to hang out with people you like and trust and shared context allows you to relax and communicate easily. I do not think, however, that hanging out with your friends is exclusive of caring about or listening to people outside your immediate group of friends. This is especially true if you care about diversity or the pursuit of truth. The difficulty with blogs is that a variety of contexts are collapsed and the conversation with your friends, the conversation with a larger community and the general pursuit of diversity and "triangulation" all happens in the same place.
Normally, chatting in the kitchen with my family, hanging out at a geek conference and giving a plenary at an international conference are different contexts for me where I am performing a different facet of my identity and where my mind is in a completely different mode. On my blog, I somehow mix all of these together.
I think that in the real world the amount time communicating with your strongs ties is generally greater than the amount of time communicating with your weak ties. Weak ties are like transferring information across communities and boundaries whereas communicating inside of your group is more like digesting these thoughts. I suppose the question is whether talking about things among your friends tends to reinforce and amplify misconceptions or leads to greater understanding of the issues.
On the one hand, sharing context allows you to communicate efficiently and place new ideas into existing frameworks without the risk of constantly talking past each other. On the other hand, it limits your ability to "think outside the box" and a poorly organized group probably causes mutual back-patting. I think that's what the echo chamber is currently being blamed for causing. Shouldn't we recognize the fact that people will hang out with their friends and create communities and try to focus on how use these communities together with our weak ties?
I think that the project that Ethan and I are planning is an example of this. The idea is to take a group of bloggers to Africa. The strong ties allows us to have a group of people with whom we share a context so that we can support each other and work together to think about and create action based on things we see and learn in Africa. Going to Africa is an attempt to forge weak ties with a community outside. I think that without the smaller group of friends, trying to tie my Africa experience into my daily life would be more difficult and I think that going to Africa will enrich my local community with lots of new information and culture. I think the perfect balance is what we are trying to achieve.