Before we meet the contenders, here are general considerations that you ought to keep in mind. These are general pros and cons when it comes to online office applications, and not necessarily specific to the ones mentioned here. This is especially true of funding (the last point in the "Disadvantages" section): many new 5-employee companies have been bought over by the biggies; companies that otherwise wouldn't have been able to stay afloat for a long time. For example, Google, which bought Zenter for its Powerpoint-like capabilities, and Yahoo, which recently bought Zimbra.

Advantages of Online Applications:

- Can be accessed from anywhere
- Platform independent -- can work on any operating system
- Simple and intuitive interface
- Quick and easy signups
- Documents can easily be shared and collaboratively worked upon (no version issues)
- No Hassles of housekeeping with updates and security hassles at your end
- No licensing fee: they're completely free (though some may charge for advanced features
- Some have portable editions, which can be accessed directly through portable devices like iPods

Disadvantages of Offline Applications

- Slower than their desktop counterparts
- Not (yet) as mature as Microsoft Office
- Too dependent on Internet connectivity (though some have offline support)
- Not always 100% compatible with complex formatting (especially true of spreadsheet programs)
- Dialup users, as well as limited account users (MTNL) watchout -- as a lot of data is transferred to and fro when working with online applications, especially if working with graphics-heavy presentations
- Not all the companies backing these online services have a sound business model -- meaning, if they fold, say goodbye to your data too! (or you may get enough grace time to transfer your documents)

Note:- The word "documents" from here on indicates Word, Excel and Powerpoint type of format, and not just Word documents as generally referred to.