Tag Documents with SharePoint 10
SharePoint 2010 lets you tag things so that you can find them later and that people with whom you share your tags and notes via social networking sites also can see them. So, for example, if you find a document that you like and want to encourage others in your network to read, you can apply a tag to the document and then that tag is associated with you so others viewing your profile can see the tag.
Don’t panic: SharePoint 2010 tags and notes can be made private so that only you can see them, and you can also delete your tags whenever you want. To tag a document and then view your tags:
Browse to the library containing the document.
Select the document using the check box in the list view.
Click the I Like It button on the Document tab.
SharePoint briefly displays the Add Tag confirmation message, and the item is saved to your tags and notes, visible to your colleagues in your profile Tags and Notes tab.
Click the arrow beside your name in the upper-right corner of the page and choose My Profile from the drop-down list.
Your profile page displays.
Click the Tags and Notes tab.
In the Activities For: section of the page, you see an entry for the tag you just entered.
Select the Make Private check box beside any activity so that only you can see it.
Now only you can see the item you marked as private.