Zoho recently released a set of APIs that lets anyone write their own program to use Zoho Writer and Zoho Sheet data [disclosure: Zoho is a sponsor of Read/WriteWeb]. As Matthew Ingram explained, it "means that other companies -- online storage providers such as Box.net, Carbonite or Mozy, for example -- can easily build support for Zoho's services into their own products."
Also Google recently announced their Google Spreadsheets API, as noted by John Musser. This API is part of the GData set of APIs that Google has already utilized in Google Calendar and Google Base. Here's how it's described:
"The Google Spreadsheets data API allows client applications to view and update Spreadsheets content in the form of a Google data API ("GData") feeds. Your client application can request a list of a user's spreadsheets, edit or delete content in an existing Spreadsheets worksheet, and query the content in an existing Spreadsheets worksheet."
These APIs from Zoho and Google enable other client applications to work with and store their data, which essentially blurs the line between desktop and web applications. As you know, one of the primary benefits of web-based office apps is that they enable easier collaboration on documents and files. Another benefit is that documents or files are always synced. So these APIs give users more choice about what application to use to work on their documents (i.e. it can be using the online host app, or on alternative desktop or online app), while at the same time enabling the collaboration and sync that users of web-based office software have become familiar with.
As well as the API, Zoho also released a plug-in for Microsoft Office and a widget that makes Zoho behave more like a desktop application. Zoli Erdos has a great post explaining more. All of these new features by Zoho are aimed at 'embracing' Microsoft Office, which makes it ultimately easier for MS Office users to try out a web-based offering like Zoho. R/WW readers will recall JotSpot CEO Joe Kraus and his embrace and extend theory of Web Office, in which he said that Jot Tracker's aim was to not only to embrace Excel's functionality - but extend it in a Web native way. This is essentially what Zoho is doing too.
Ironic that 'embrace and extend' is now being used against Microsoft in the Web Office space, when in the early days of the Web Microsoft used the same kind of strategy to defeat foes like Netscape and Sun in the consumer Web arena.