Crap I got ISTP for latest posts too... Maybe it's going off the design of the blog/site itself. That's rather boring. Tumblr gives different results sometimes I noticed, but that might just be design too. The typology central version of this is a bit more accurate (I believe it goes off of word choice and common phrases, but that's a guess).
I see. The [only] plausible answer here, it seem(s) to me, is that we are all ISTP™ // ISTJ™ hybrid(s).