Can del.icio.us be a PR measurement tool?

Andrew Careaga just discovered del.icio.us as a PR measurement tool.
His point is that del.icio.us may give you insight into which online sites are most popular for niche readerships, which in turn may help you adjust your media relations efforts. He's absolutely dead on. We recently conducted an in-depth analysis of del.icio.us and other social bookmarking sites for Georgia Tech and found that social bookmarking sites were in fact a great measurement tool, but we found that del.icio.us isn't nearly as robust as a metric as  digg, stumbleupon, etc. .