Harry Potter was watching the Slytherin table. It looked a little different this year, but had started to actually settle out. Particularly the fifth years, in which, for once, Draco soddin' Malfoy seemed to be sitting off by himself. He certainly wasn't anywhere near Crabbe and Goyle, who were sitting near Nott, instead. Malfoy still had Pansy Parkinson sitting beside him, and the Greengrass girls were sitting in between - in such a place that they didn't look like they were favoring either side. Other years had similar arrangements, Harry saw, as he watched carefully. But, he thought, the arrangements didn't quite make sense to him. The Greengrasses, sure, he knew they weren't Death Eaters - but Malfoy was, and Parkinson's family might as well be. So why were they sitting so far away from Goyle and Nott? What was going on? And Zambini was flat out gone. Harry wanted to call that cowardice, and perhaps it was. But he wasn't always sure he wouldn't have preferred to have cowardly parents.
And Harry had seen, from discrete glances around, that the books he'd purchased at Diagon Alley had gone mostly to Slytherins. Not all the Slytherins (Nott, notably, didn't have one). But Why? Why would Slytherins, of all people, be unable to go to Diagon Alley? Certainly Snape wouldn't have asked Harry Potter to do something without a solid reason - he wasn't one for owing people favors, and Harry Potter least of all.
Harry wanted to ask someone, wanted to talk with Dumbledore, to do practically anything other than sit, and watch, and wait. Trying to divine human relationships was harder than predicting the future with tea leaves.
[a/n: Welcome to HarryWorld, where he really hasn't had the training first-year Slytherins get. Leave a review?
This is how Draco Malfoy decided to place people (although, to be fair, placing the Greengrass girls anywhere other than true neutral would be likely to see them say no, so Draco did what he did to retain authority there)]