On Pages, when the author of the page is added Notes, Links, Photos and Videos, this can be done both on his own behalf and on behalf of the page (Screenshot - 51.jpg).
Events, File and Polls can be added only on behalf of the page (Screenshot - 52.jpg).
How to make files and polls too can be added on behalf of the user and on behalf of the Page.
In the Polls widget, the username of the poll is displayed in the name of the user (Screenshot - 53.jpg), in the activity stream (Screenshot - 54.jpg) and the list of all polls (Screenshot - 55.jpg) - the Page name.