There have been several attempts to unseat Microsoft Office, including Sun\u2019s StarOffice and Evermore Integrated Office. The former is a locally installed Java-based Microsoft Office-like suite, while the latter is a set of standard Windows applications. Neither has managed to make much of a dent in the marketplace. A new Office-like suite that goes in a somewhat different direction is ThinkFree Office Online.Like StarOffice ThinkFree is Java-based - but rather than locally installed, ThinkFree is based on downloaded applets that use ThinkFree\u2019s servers as the default data storage (you can also load and save documents to local storage).ThinkFree Office Online applications can create, open, and edit Microsoft Office-compatible documents from the Web or local storage; post documents directly to a blog without any conversion, create powerful Web-based presentations and convert documents to PDF format.ThinkFree Office Online\u2019s applications - Write, Show, and Calc - all have features similar to their Microsoft Office counterparts, sharing file formats along with all of the major and many minor facilities required for compatibility.I tried all of the applications and was really impressed - this is one of the best attempts at delivering Office functionality that I've come across. There are no obvious rough edges (ThinkFree Office Online is, after all, still in beta), and as far as I can determine there is little that is anything remotely like a \u201cshowstopper\u201d - if you discover any issues please let me know.In particular I was impressed by Calc. I loaded several spreadsheets that I had previously created with Excel, and they ran perfectly, including - and this was what really impressed me - the formatting. Under Calc my heavily formatted spreadsheets looked just as I had created them.Performance appeared to be fine. Local loading and saving was excellent while the same operations from the remote server were as you would expect from file operations handled across the Internet.ThinkFree Online Office is in beta and free. On sign-up you get access to all of the applications and 30 MB of storage.To support the service, ThinkFree plans to display ads. According to the terms of service:\u201cThinkFree serves relevant ads using a completely automated process that enables ThinkFree Online Office to effectively target dynamically changing content, such as document and\/or e-mail. No human will read the content of your file and\/or e-mail in order to target such advertisements or other information without your consent, and no file or e-mail content or other personally identifiable information will be provided to advertisers as part of the Service.\u201dInteresting.This is definitely a service to watch. With the right backing (are you listening Google, Yahoo, Amazon and eBay?) ThinkFree Online Office\u2019s approach could address the personal productivity requirements of many non-professional users while acting as a back-up resource for professionals who are mobile.