Syncplicity offers a free and a premium synchronization service for Google Docs. To try it, visit the Syncplicity Web site and then create an account. Once you do this, you can download and install the Syncplicity application.

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If you want to sync Google Docs, click the "Google Docs (new!)" option on the Syncplicity Web site menu.

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When you click the "Link to Google Docs" button, you are prompted to authorize your Syncplicity account to communicate with your Google Docs account. You then can choose a folder to synchronize with Google Docs or optionally create a new one. The free version of Syncplicity allows you to synchronize up to 2 GB of documents between your hard drive and Google Docs. Paid versions of Syncplicity allow up to 50 GB of files to be synchronized. Now Google Docs can be emailed from your local machine or from your Google account with ease.
Syncplicity actually maintains two versions of your files: the Google Docs version online and your local rich text version on your hard drive. This means that Microsoft Word features like comments and change tracking will not be available from the Google Docs version of your file. When changes are made to the online version, Syncplicity will create a new version of the document on your hard drive rather than overwriting it. Another thing: Syncplicity is not able to sync Google Docs that have been deleted, moved, or renamed.