Plain White T's: Hey There Delilah
This is a thumb and finger picking technique known as Root→Chord where you alternate between the single Root (bass) note with your thumb and the rest of the chord with your fingers. It is common in Irish classical guitar music and I also came across it recently in 'The Don' by The View.
Vital Tip: The red tab are notes outside of the chord you are holding, played once at the end of the bar. This is used to move more smoothly between chords.
VERSE
D5 F#m D5 F#m
E [-----------------|----------------|----------------|----------------
B [---3---3---3---3-|--2---2---2---2-|--3---3---3---3-|--2---2---2-----
G [---2---2---2---2-|--2---2---2---2-|--2---2---2---2-|--2---2---2-----
D [-0---0---0---0---|4---4---4---4---|0---0---0---0---|4---4---4---4---
A [-----------------|----------------|----------------|----------------
E [-----------------|----------------|----------------|----------------
Bm G A Bm A
E [-----------------|----------------|----------------|----------------
B [---3---3---3-----|--3---3---2---2-|--3---3---3---3-|--2---2---2---2-
G [---4---4---4-----|--4---4---2---2-|--4---4---4---4-|--2---2---2---2-
D [-----------------|----------------|----------------|----------------
A [-2---2---2---0---|--------0---0---|2---2---2---2---|0---0---0---0---
E [-----------------|3---3-----------|----------------|----------------
CHORUS
D Bm D Bm
E [-----------------|----------------|----------------|----------------
B [---3---3---3-----|--3---3---3---3-|--3---3---3-----|--3---3---3---3-
G [---2---2---2-----|--4---4---4---4-|--2---2---2-----|--4---4---4---4-
D [-0---0---0-------|----------------|0---0---0-------|----------------
A [-------------0---|2---2---2---4---|-------------0--|2---2---2---4---
E [-----------------|----------------|----------------|----------------