Great service Rated 5 out of 5 stars
The privacy concerns I read in another post are overblown. Here is what their TOS says
"By submitting content to or generating metadata, content and content enhancements through the Zemanta service, you grant Zemanta ltd. a non-exclusive perpetual, sublicensable, royalty-free license to that metadata."
non-exclusive means you still own your content. A lot of services do things like this and its especially smart for Zemanta because that meta content will help them tune suggestions for users.