The extension Hide Empty Attributes allows hiding product attributes that contain no value.
For such attributes Magento displays "N/A" or "No" depending on attribute type (select or text). This extension can
- hide such attributes on the product view page
- display dashes on the product view page instead of "N/A" and "No" (you can change it to any other character in the extension settings)
If an attribute is a boolean (Yes/No), there will always be some value in the database, since there is no way not to select value on the product save form. So the extension allows to hide the attributes, that have the value "No".