Resolution?

In blues, it's extremely common for "all" the chords to be dom7s. This gives blues its typically "restless" quality. In a song played with all 7th chords, there is no "resolution" as such.

What happens is that each chord "pulls" you towards the next.

In the example above (sorry, I'm not familiar with the song in question), it's in they key of E, so it presumably starts with the E7. This chord wants to "move" (resolve) to A and does, but finds no rest because that's a 7th too. Same with the B7. That wants to resolve to E, but gets an E7 instead.

This is typical of blues although not all blues are written with all 7ths. Blues songs do not always "resolve" properly to a plain triad and sometimes end on that edgy, unresolved 7th chord.

That C7 is slightly unusal for a blues, but may be thought of as a chord substitution from the parallel minor (borrowed bVI). It is often called the "Buddy Holly chord" because he used it a lot, as did the Beatles. It is most commonly used as a passing chord towards the V.

Anyway, the song is in E and uses the I7, IV7, V7 and bVI7.

Thanks, that's kind of what I figured it must be.

Another way to look at the C7 in this case is as a substiture for Am7(b9), giving you a minor IV to I feel. That makes the song I - V - IV - iv - I, which is used a lot in various styles of music.

Peace