Sparrow
Used by 24 peoplegmail.com ↗

“I use Sparrow as my mail client, and I don't host my mail on GMail.”
Ramsey Nasser Interview, Computer scientist, game designer · via Uses This 
“I use Sparrow for email, but really don't like it.”
Abby Seymour Interview, Bookbinder, jewelry maker · via Uses This 
“Speaking of columns, I use Sparrow for my work e-mail, which is also a single column and sits on the right-hand side of my screen.”
Daniel Sinker Interview, Director, Knight-Mozilla OpenNews · via Uses This 
“I love bits and pieces of Sparrow , but stick with the classics for now.”
Toby Boudreaux Interview, Technologist, programmer, product designer · via Uses This 
“For email I started using Sparrow recently, because I really really love how it can take up far less space than most email apps.”
Ed Finkler Interview, Web developer (Gimme Bar, Spaz) · via Uses This 
“I recently started using Sparrow for email, since all my email is Google Accounts-based.”
Wilson Miner Interview, Web designer (Rdio) · via Uses This