Koiwazurai no Ellie

Eriko Ichimura spends her high school days in complete obscurity. Her sole hobby is staring at handsome, smooth-spoken Akira Oumi, and tweeting her daily fantasies under the screenname "Lovesick Ellie." One fateful day, she accidentally bears witness to Oumi-kun's true self—and if that weren't enough, he sees her mortifying Twitter, too! Follow along with a plain, perverted girl, a two-faced boy, and their curious romance!
(Source: Kodansha USA)
Notes:
-Chapter count includes 2 extras.
-Kodansha released a 13th volume that included an extra chapter and the one-shot "Hikaeme ni Itte mo, Kore wa Ai". This volume was only released in digital format.