The blogging community has characteristics different than other groups already. Firstly, the people in the group are technically savvy to a certain degree, have time to blog and post, and want information. This narrows the community down to a small group among Catholics in general.
Secondly, the people in the group have an unusually high level of reading comprehension, like to pursue the Teachings of the Church and want to grow as adults. The Catholic Faith has always been "intellectual", even in opposition to the Protestant denominations, which undermined the rational and emphasized experience, as the Pentecostals do today. This great heritage of the rational merged with the faith life is essentially Catholic.
Thirdly, these communities are self-selecting and tend to be either conservative, or orthodox, or liberal or liturgical and so on. If one looks at the blog lists of many of the bloggers, one sees overlaps, which indicated a community of sorts.
Lastly, the blogging community is temporary and immediate. That is, it responds to needs and events which are "now". Father Ray Blake's blog and Father Z's blog have responded in depth to areas needing action, political and financial, for example, in the past weeks especially.
But, the temporariness of the blogging community needs to be addressed more seriously. If a lone blogger in Germany cannot find the community with which he or she can share Faith, except online, this is a possible area of real concern. Even me, in a semi-rural area of Ireland, rely on bloggers for my main source of Catholic conversation daily or weekly. The local church communities no longer exist as communities, and the anti-intellectualism of most Catholics leads to isolation. How long we can rely on the virtual communties is a key discussion, as real communities must function in close proximity. I was in a lay community for seven years, and the day-to-day life of a basic Christian community barely resembles the virtual. However virtual communities exist now, this will change and we shall have to adjust in ways which may demand moving or being completely isolated.