Hi Glen,
I was doing an extensive study on the word earlier this year. I've found that we mostly just pass it over while reading the Psalms. I was reading the Psalms one day and thought what does it mean - why is it there - so I decided to research it. I believe that every word in the bible has meaning otherwise they wouldn't be there.
I found out that it is meant for us to stop and really weigh / measure what was just said as in:
Psalm 4:2
How long, O men, will you turn my glory into shame ? How long will you love delusion sand seek false gods ?
Selah
Psalm 68:19
Praise be to the Lord, to God our Savior, who daily bears our burdens.
Selah
I found a very informitive study online. If you want, I can email it to you.
JC