You might find it useful to allow a trusted friend, co-worker, or significant other to make edits to your calendar without giving them your password. Yahoo! Calendar now lets you take Calendar Sharing a step further by allowing Special Friends to manage and edit your schedule.

What Special Friends can do:

Add new events to your calendar.
Send out an invitation on your behalf.
View, edit, and delete events that have Public and Show as Busy event permissions.
See only the word Private on your calendar for events that you have marked as Private.
Add a task to your task list.
What Special Friends can’t do:

View event details of Private events.
View Private tasks.
Respond to invitations received from others (this is done through email).
Import, export, or synchronize into your calendar.
Change your calendar options.
Please be responsible when using this feature.

Check the terms of agreement. They have been given the right to post events by you. I hope this helps. Always read the terms of agreement.