I too am interested in the ability to annotate on powerpoint. I know that workarounds are mentioned here but that does not assist in annotating during live presentations. Skitch seems to be much smoother and more efficient than the built in Microsoft ink. I have paid for products such as Smartboard and am finding that in higher education, their annotating is limited and rather clunky. Skitch is smooth and flawless! I have been very impressed with it!