Weblogging convention has it that a weblogger (blogger) puts a list of links to other weblogs he / she is currently reading, down the side of the weblog page. (In TheGutter) (For example : PhilsBlogRoll) This list both positions the blog in the BlogoSphere , and bends the shape of the BlogoSphere. BlogRolling is typically reciprocated by others on the list, so BlogRolls make a tight, interconnected cluster of weblogs, representing a cluster of common interest or thought.
Thus the blogroll is a place, a well of web gravity, where according to TheFlowInternet, a story of interest falls in and finds itself perpetuated in resonant discussion between members of the roll; wheras it is soon gone from other nodes.
Subscriptions not dynamic enough? : http://www.stoweboyd.com/message/2006/05/scoblestrapan.html