UPDATE 02/08/2012, I have written an important follow-up to this blog post at Power View in SkyDrive revisited which has better news than what I have written below. Please read that blog post as well as this one.
Sean Boon has begun an interesting blog series where he is analysing data from the Olympics using using Power View in Excel 2013, his first post in the series is at Visualizing the Olympics with Power View in Excel 2013: Day 1. While the capabilities of Power View itself are impressive this gives me an opportunity to highlight what I think is a massive failing in the whole Power View Excel in 2013 story.
Sean provides a link to a SkyDrive folder, Power View Olympics, where he is collecting his demo workbooks. I clicked on one of those workbooks in order to view it in my web browser and I saw this:

“Unable to load the requested workbook”
Oh, did they forget to tell you? Workbooks containing Power View reports cannot actually be viewed on SkyDrive. Whoops! What is even more vexing about this is that if the workbook were hosted on SharePoint then I *would* be able to view it using my web browser, however unless I am mistaken, with SharePoint I can’t share it with the whole world like I can using SkyDrive! SharePoint offers online Power View while SkyDrive offers frictionless sharing – neither offers both! This glaring lack of parity between SharePoint and SkyDrive is, to my mind, the most infuriating part of Microsoft’s Excel collaboration story.
None of this came as a surprise to me. I was lucky enough to be invited onto the Office 2013 Technical Preview back in 2011 and I discovered back then that Excel workbooks containing Power View reports would not be viewable in SkyDrive; I fed back vociferously that this was a big failing, I guess that feedback fell on deaf ears.
Welcome to office collaboration, Microsoft style! You can share your Power View workbooks with the entire world but if anyone wants to actually look at them they’re gonna have to install Excel or SharePoint! Meanwhile if you want frictionless, collaborative, immersive BI on the web other offerings are merely a click away!
Power View in Excel 2013. So near, yet so far!!
@Jamiet
For more scathing opinion on Microsoft’s Excel collaboration efforts take a read of: