Are there any Katy Kats here? I was just listening to her superior album and realized Up All Night (album) is actually VERY similar.
The overall theme is relationships and love. They include pop songs built on simple beats, with up-front vocals for easy sing-alongs. Smash lead singles that are pop/rock with electronic influences (WMYB & I Kissed A Girl); lessor follow up ballad singles (GBY & Thinking of You); the weirdo of the albums (I Want & Ur So Gay); the heartfelt ballads (MTT, Same Mistakes & Lost, ISB), the electronic dancey songs (Everything About You, Stole My Heart & Hot and Cold, WUIV); then the rest is just a mix of pop, pop/rock, electronic songs.
They even use the same instruments of piano, synths, and guitar.
Plus they both share the word "One"