Although you have a company Exchange server and shared calendars you find that people outside your company are becoming confused over the arranged terms? Is it difficult for you to find a new suitable term for the project meeting or arrange a shift in the milestone in your schedule?
Do you lack the possibility to plan the entire project? Approve future meetings in the team? Assign documents to events and coordinate and monitor the progress of works any time and from any place?
Modern calendars will enable you to clearly organise your time and time of your colleagues.