I was genuinely amazed when I first saw a demo of Prezi at the most recent The Next Web conference, and wrote that it was simply the coolest online presentation tool I'd ever seen. I still stand by that statement, and I'm apparently not the only one impressed with what the Hungarian company is doing.The startup just secured an undisclosed amount in Series A financing from Scandinavian VC firm Sunstone Capital and is adding Twitter co-founder Jack Dorsey to its roster of company advisors.