I second some of what I have stumbled across in the latest posting at homoLudens. (See also his earlier posting. I'd like us to try out Tinderbox. Can the Department of Digital Strategy pay?) I have a number of lesser blogs on the go already — I am, indeed, treating blogs as an on-line resource for noting, and several of these blogs are not ones I want yet (if ever) to put in the public domain.
On the other hand, I am much enamoured of blogging as a medium for good writing. I find this sentiment echoed explicitly in some of the comments on this teacher's blog and also implicitly in the fine writing of, for example, Harry's Place, Oliver Kamm, Clive Soley and Norman Geras. Blogs do have a role as signposts, but they can also be much more than (just) this.