Yes, the dominant definitely has a lot of substance to it.
Here is a quick overview:
The dominant chord name comes about because it is built on the 5th scale degree, which called "dominant". A list of the all the scale degree names is given here:
Music Theory Basics
The most common form of the dominant chord is to play it as a 7th chord, which makes it a "dominant 7 chord". The function of the dominant 7 chord (ie, it's main purpose in life
) is to create a "pull" towards the tonic chord. Just playing this chord by itself with no other chords creates a VERY strong pull towards the tonic chord.
For example, play a G7 chord (see below), let it ring for a little bit and feel the tension it creates. Then follow it up with a C major chord. You should hear how nicely these two chords go together.
To play a G7 chord:
1st finger = 1st fret, high E string
2nd finger = 2nd fret, A string
3rd finger = 3rd fret, low E string
Then from there go to a C major chord.
If you don't hear the connection right away, go back and forth between them a few times. You'll know it when you hear it.
G7 is the dominant 7 chord of C major (C is the tonic), so G7 creates a very strong pull towards C. Every key has only "ONE" dominant chord, so anytime you play a dominant 7 chord, you automatically create a pull towards the tonic for its key.
Another couple examples,
E7 pulls towards A major
A7 pulls towards D major
You can try these and hear the relations as well:
E7:
Finger an E major chord but remove your finger on the D string (so that it plays open).
A7:
For an A7, finger an A major chord but remove your finger from the G string (so it plays open).
I don't know how much music theory you've had, but if you're interested in how these work and how to figure them out, I have much more details on these in my music theory lessons
HERE.
If you're relatively new to music theory, I'd recommend starting with the first link called "Music Theory Basics" and go through them in the order that they are listed. The last part of the Modulation link gets into the "interesting" stuff.
Although it's done for diminished chords, they are
VERY similar to dominant chords (they have the same function) and the same theory applies.
Hope that helps.
-tkr