Microsoft is yet to capitalise on its dominance by taking its applications online. Here we assess the free, web-based competition to its new Office 2007 suite.

UPDATE, 1 May 2007: brand new review of OpenOffice 2.2 and brand new review of Star Office 8.0.

There are many free or low-cost online competitors trying to nibble away at Microsoft's $11.8bn Office pie by pulling together productivity suites with online document storage and innovative sharing and collaboration features. These options can prove useful for group efforts and the price is certainly right. But none can truly challenge Office - at least, not yet.

We've taken a thorough look at four of the biggest free rivals to Office 2007.

OpenOffice Writer

Click here for PC Advisor's review of OpenOffice Writer, the longest-standing free alternative to MS Word.

OpenOffice Calc

Click here for PC Advisor's review of OpenOffice Calc, a spreadsheet application that compares well with its Microsoft Office equivalent.

Google Docs & Spreadsheets

Click here for PC Advisor's review of Google Docs & Spreadsheets, Google's web-based office software.

Mozilla Thunderbird

Click here for PC Advisor's review of Mozilla Thunderbird, a useful one-stop shop for communication.

Google recently launched its free Google Docs & Spreadsheets service, combining its previously separate word-processing and spreadsheet applications. ThinkFree and Zoho, in their more extensive suites, offer PowerPoint-style presentation programs. These contenders are all free to use and allow you to save documents in a variety of formats, including HTML. A fourth contender, gOffice, charges 99¢ (50p) per month for its limited word processing and spreadsheet programs.

Beyond Office

These sites have something that Microsoft doesn't: the ability to create easily shareable documents, spreadsheets and calendars, on any PC that's connected to the internet, regardless of the OS and without the need to install expensive software. After creating or editing your document in Google's offering, one-click publishing puts it on public display at a unique Google-created URL. You can then email your colleagues a link so that they can edit your document. ThinkFree and Zoho offer similar sharing options.

As suites, these services offer useful central document repositories that you can access from any system with a web connection. Google allows storage space for 1,000 documents and 100 spreadsheets, while ThinkFree and Zoho offer 1GB of free space. Pay a monthly charge and you can add more. In contrast, Office saves only to your hard drive and Microsoft has no plans to introduce online storage.

All the suites broadly mimic Office's interface with familiar menus and toolbars, but create a desktop application feel with Ajax (asynchronous JavaScript and XML). Largely credited as the magic behind Web 2.0, Ajax web programming means users don't have to wait for a page refresh after making changes. Plus it can enable right-click menus specific to the online application instead of to the web browser. Although ThinkFree uses Ajax for quick editing, it loads a slower and more resource-hungry Java Virtual Machine for its more feature-rich power-editing mode.

All the services permit quick rollbacks to previous versions of files. Zoho shows the differences between versions without fully reverting. With varying degrees of success, all can upload and import Office files, although formatting often doesn't line up correctly. Microsoft has plans to create an online version of its entry-level Works package, yet its opportunistically named Office Live website doesn't actually offer any online Office applications.

No huge threat yet

In some ways these suites begin to fulfil the promise of the web, but Office - highly polished over the years - has a clear lead in overall features and suite integration. In the online suites, you won't find this degree of integration and much of the advanced functionality present in established versions of MS Office, let alone that in Office 2007. In particular, the presentation applications don’t come close to the feature-set you'll find in Microsoft's PowerPoint.

What's more, much of the 'suite' aspect consists only of your using the same log-in and - except for Zoho - storing all your documents in one place, without much in the way of other tie-ins between the applications. For example, if you cut-and-paste part of an Excel spreadsheet into a Word document, you'll get a converted Word table that preserves the rows, columns and shading. The online options, in contrast, will paste the content in roughly the same layout but won’t put it in a table.

Fee-based options

Of course, to stay around long enough to continue to develop, these Office challengers need money. Google has deep pockets, but the other vendors must supplement their free or low-cost consumer offerings. The online suites that survive will no doubt continue to evolve quickly. However, Microsoft is not standing still and Office 2007 will have its own collaborative online tools for both enterprise and consumer users. Free is a big draw, but for serious work Microsoft needn’t feel nervous about losing Office users just yet.