I became interested in computers through open source software and the hallmark of OSS is the community. Throughout the years I have subscribed to mailing lists and the like in addition to spending time on IRC and generally being a part of the community. Specifically, I have been interested in the GNOME community and as such, I became exposed to Planet GNOME. A "Planet" is a loose term for an aggregation of blogs based on some topic. Planet GNOME for example, includes blogs of GNOME developers.
When I became interested in XML while I was in college (man, was I cool!), I searched for a "Planet" for XML related topics. Having read Ed Dumbill's blog for a while, I found Planet XMLHack. It is not perfect and there are a few bloggers whose posts get duplicated, but overall it is a great resource. It provides a great deal of insight into the happenings in the world of XML from the perspective of those who define it. Take a look sometime!