Clearly, Othello is a tragedy. First, there are all those deaths (**spoiler alert!** Desdemona, Emilia, Othello, and Roderigo D=). Then there's Othello, who is, as the title would tend to indicate, the story's hero, in spite of all Iago's stage time. His tragic flaw, one might argue, is that he is too trusting of Iago. Certainly, he wasn't too trusting of Desdemona, although he must have felt that way. (We can see this from the way he lays into her, calling her a "whore" and an "impudent strumpet" in IV.ii.71-80.) Really, he's just got really awful instincts about who to trust.
I also think the play might have had elements of a melodrama. If something like this actually happened, it would be all over the news, and we would all probably sigh and change the channel because who needs the hysteria of another tragedy? The story'll make its way into your arsenal of knowledge through some means, inevitably, so it might as well be put off another hour or two.
I don't know that the audience's ability to classify the play can really be tied into their watching experience. If it was a comedy, that might be different, but I'm thinking of a comedy as it is defined today. When people know something is a comedy, they have a tendency to laugh harder, as if they're compelled to follow the conventions of it.
This guy apparently disagrees; he thinks we feel everything in general more in a group of people. I dunno. I personally don't laugh aloud at funny movies when I'm by myself. More emotionally evocative movies and such cause more embarrassing reactions that are probably easier to allow in the privacy of one's own home. In any case, I don't really think knowing this was a tragedy was essential to my reading throughout, although perhaps it gave me the sense to avoid real attachment to any of the characters.
Furthermore, 1119 is very close to 1117, which was my Girl Scouts troop number.