If you are using Tameday within your organisation it is a great way to share information.
People who are included in the same Project as you can see your to-dos, events, discussions etc. They might not be specifically mentioned or assigned to these but they can view it from the Activity screen and in Search.
Users not in the same Project will not be able to see any of your project specific work, to-dos, events, discussions etc. and vice versa.
Likewise with Teams. Only user within a Team can view the information stored within that Team, e.g. Management team, finance team, Admin team etc.
Each Tameday account has a Company HQ. We'd recommend this for company wide announcements, events and information that would be beneficial to everyone in the organisation.
If you would like to add something for yourself which no-one else can access use the Locker project. This isn't accessible to anyone else and is unsearchable in the Search and does not appear in the Latest Activity.