The free version of ContactOffice is very restrictive in terms of number of users, data storage capacity, etc. Thus, it has been decided that this tool will not be appropriate for evaluation within the scope of this project.
It is worth noting, however, that ContactOffice also has a beta version, found at beta.contactoffice.com. This version is being developed using AJAX and the Google Web Toolkit. This new version may have a better user interface and increased capabilities.
ContactOffice Launches New Version of Web Office Tool
Manage your data with ContactOffice