If you feel like hes really copied your work without giving you credit, approach him over email or twitter privately, and ask him to rectify it.

Make sure you keep a copy of the original, infringing slideshow of his, incase he tries to change it after the fact and cover things up.

If he is uncooperative or unresponsive, escalate the issue. Take it to other members of the MS team on twitter, on fb, etc etc. Avoid direct attacks on this persons character, and instead make sure to frame it as you, the original author, just wanting his proper credit. If you can build up pressure, at the very least he'll be shamed away from doing this sort of thing again.

But try to reach out to him in a professional, non threatening manner first. You might be surprised by the response you get