Isolated Queen's Pawns - another go.
If you have an Isolated Queen's Pawn, you have outposts on c5 and e5, a half-open e-file, more space, more mobility, and more chances of attacking - on either side, I guess, but the e5 outpost suggests the King's-side. On a good day, it works like this:
If you have an Isolated Queen's Pawn, you have a pawn which, if attacked, will need defending by pieces, and which will restrict the activity and flexibility of your pieces. In an endgame with few pieces on the board, the advantages disappear and the disadvantages are more marked. Defending an endgame with an IQP is not a lost battle, but it's a tough one. On a bad day, it happens like this:
Terrific transformation of advantages by Karpov, switching to a pawn sacrifice and an attack on the King to finish. The other good bit is seeing how manoeuvring with one weakness in mind is used to tempt (or force) other weaknesses, and the extra burden is too much.
Well, all so well and good watching the GMs play IQP positions, but are they too hard for club players? Not a bit of it; here are the same arguments for and against put by club players:
Regis-Evans, 1995 Kindle-Pope, 2012
The change in the pawn structure to an isolated pawn-couple and eventually hanging pawns, which we saw in Sean's game, is very common in these positions. The advantages and disadvantages of hanging pawns are similar in character to the IQP.
The formula taught by Nimzowitsch was restrain, blockade, destroy! If the IQP is not restrained, then it can lunge forward with great effect, either blowing the position open for the active, flexible White pieces, or even pushing on for a try:
The pawn can sometimes advance, but be as weak or weaker on its new post.
GM play has been profoundly agnostic about IQPs; it's a matter of style as well as analysis. I guess these days they're generally avoided in favour of more complex and flexible structures.
The ...g6 move, posting the Bishop on the long diagonal, is a common manoeuvre, bringing the piece to attack the IQP in a way that echoes the main Schlechter-Rubinstein line of the Tarrasch Defence. It's very hard, but not impossible, to break through on g6: