I guess I don't have a source for this and don't know that it's strictly true, but tumblr is certainly /designed/ with collated dashboard reading of content as

I guess I don't have a source for this and don't know that it's strictly true, but tumblr is certainly /designed/ with collated dashboard reading of content as its intended use case. The actual blogs at tumblr subdomains are incidental to how registered tumblr users use tumblr, and those are the people tumblr is focusing on. I think the only blogs whose content are primarily read at the blog level are those tumblr blogs that are actually some organization's website blog and which are consequently well-designed.