[thesethings]

That does address one's own Tumblr Dashboard when logged in. And there has been one browser extension that's gotten quite popular- Missing-E. But it's gone through battles with Tumblr, and also doesn't solve the "global" issue: I don't just wanna see stuff about me, I want to discover stuff outside my account. Example, "Who blogs about farmers markets in Miami?" Something like this is app-able in twitter, but not Tumblr given its current API.

I do still recommend checking out Missing-E. Don't put it on all your browsers (it can't keep up with Tumblr changes, and sometimes freezes). But it is helpful. (It's available for FF, Chrome, and Safari.) http://blog.missinge.infraware.ca/