Just heard that David Karp's tumblr, beloved platform for re-bloggers, photo-bloggers and cool bloggers who need places to park their precious overflows has raised $1.5 milion from Union Square Ventures and Spark Capital, which led the company's first $750,000 round a year ago. It's always a good sign when the VCs re-up for the B round, as they did this time; one would imagine that Karp's impressive stats--150,000 users a month driving 61MM page views per month and 15 MM unique visitors (no ads, folks.)