Atrament is a sans-serif font. It goes well with Proxima Nova, Lucida Grande, Facit, FF Meta Serif Web Pro, Futura PT and PT Serif Caption. If you're thinking about using Atrament then try 70px for headers. Give 18px a shot for content.
People commonly tag it as modern, conference, design, sans, informal, agency, art deco, quote, photo and headline. You can get it from Fonts.com, MyFonts, Typekit and YouWorkForThem.