Office Blogs

biased opinion here, i helped build Excel 2013.
We did a lot of investments in making it easier to work with your data. Off the top of my head here are some of the top things we did:
Flash fill : Automatically detects what you are trying to fill/parse and does it for you.
Suggest Pivottables: Select a range and ask excel to aqutomatically create a Pivot for you.
-Suggest charts: Excel suggest what type of charts work best with selected data.
Data model - Although you need Pro Plus to use powerpivot and powerview, basic functionality that "converts excel into a database" is built in. You can combine data from multiple sources and create relationships between data.
Apps for Office : A new way of programming against the productivity suite in javascript and html5
Chart enhancements: creating beautiful charts is easier and the options are more accesible.

A lot of this information is on our blog: http://blogs.office.com/b/microsoft-excel/
Twitter account: @MSEXCEL

and if your particularly inclined to data analysis and business intelligence I blast cool features and how tos on my personal account: @doppenhe

This looks very much like the REST API that MS released back in 2011 for the SharePoint hosted Excel Services [1]. Obviously that configuration required a SharePoint deployment on your own server. It looks like this new offering [2] [3] simply makes that functionality available on the MS Cloud for .xls[x] that are stored on OneDrive. IIRC the 2011 SharePoint Excel Services didn't support VBA or addins which are often critical for the heaviest spreadsheets that are most in need of serverization. I can't find any mention of addins or VBA in the docs for this new REST API, so I'm guessing those aren't supported.

[1] https://msdn.microsoft.com/en-us/library/office/ee556413.aspx
[2] https://blogs.office.com/2016/08/03/announcing-the-general-availability-of-the-microsoft-excel-api-to-expand-the-power-of-office-365/
[3] https://graph.microsoft.io/en-us/docs/api-reference/v1.0/resources/excel

I use native Outlook on my Mac for work, connected to an Office 365 mailbox, and whenever I change my password, native Outlook pops up a little webview (instead of native username/password widgets) with our ADFS SAML flow [0]. We use Duo Security as our MFA solution on another SAML IdP we have (not ADFS, but Shibboleth), and I don't see any reason why it wouldn't work within that Outlook webview in the event that we hooked it all up [1]. We also use some native Android/iOS apps (vendor apps, not in-house) where users log in with SAML, and thus could use Duo MFA.

TL;DR: web-based authentication is not just for full-fledged browsers that users type URLs into.

[0] https://blogs.office.com/en-us/2015/11/19/updated-office-365-modern-authentication-public-preview/

[1] https://duo.com/docs/adfs-30

A feature from OneNote I love and nobody knows about because of poor marketing is the "me@onenote.com" [1]. You send an email to it, it creates a note where Email subject = Note title, and email content = the note text

I linked my gmail account to it (it doesn't require to sync email between the gmail and the outlook account) and I email "me@onenote.com" all the time.

If you just put a URL in the subject of your email, OneNote will create a note with the HTML page extracted (so it's fully searchable) as well as a screenshot of the page!

[1] https://blogs.office.com/2014/03/17/email-your-notes-into-onenote-with-meonenote-com/

Tell Me is part of Office 2016 desktop edition [1]

It has been part of Office 365 since 2014 [2]:

Available now, an easier, faster and more convenient way of doing things in Word – Tell Me. Tell Me understands what you’re trying to accomplish and helps you do it faster. So if I’m trying to make my document horizontal, Tell Me knows it’s the orientation feature I’m looking for. It brings everything I need to my fingertips.

[1] https://blogs.office.com/2015/09/22/thenewoffice/

[2] https://blogs.office.com/2014/01/22/new-year-more-goodness-tell-me-footnotes-and-endnotes-and-more/

Bing won't go away. Search is more than 'searching for a term in a browser', it can and should be integrated deeply into the OS (well, at least a consumer OS) and other software products. Bing will be -- and to some extent, is -- the basis of information lookup in Microsoft products. A first, simple example of this is the 'Insights' menu in Office Online (see http://blogs.office.com/2014/12/10/whats-new-office-online/). Microsoft cannot possibly risk relying on Google in these cases as Google could break the functionality of core Microsoft products in a second.