8...b5 eliminating his pin and gaining space on the queenside followed by 9...Be7 developing normally seems like a fine plan. But your horrible mistake wasn't 8...d5?, it was 9...b5?? Much better was 9...Bxd1!, picking up the queen that your opponent left hanging.
Also his e-pawn was hanging for sometime you could of gobbled that up.
The e-pawn was not attacked until 4. ... Nf6. It was defended with a rook on 6. Re1, so there was only one chance for black to take it, that was on move 5. Let's see what happens.
The e-pawn is anything but free. Check the move list for some other variations.
I doubt his opponent would have spotted such an excellent response.
You should look up what Dan Heisman has to say about what he calls "hope chess". Basically, if you don't expect your opponent to play good moves, you're playing "hope chess" and it's not until you analyze a position based on the best responses of your opponent that you are playing "Real Chess".
Also, this position is a known opening line. I bet white has played this before and is aware of what's going on with the pawn on e4. I am fairly certain that white would have responded to 5. ... Nxe4 with 6. Re1. From there it's pretty easy to win the pawn back.
"I've heard that before and I disagree with it."
To the original poster, so there you have it. Acclaimed master Dan Heisman says one thing; HotFlow says another. A tough choice if your goal is to improve. 
Here is what Dan Heisman says about "Hope Chess":
 | "In 'Real Chess' you make sure you can meet all of your opponent's threats before he makes them; otherwise, it is 'Hope Chess.'" |
| "*Hope Chess is not when you make a threat and you hope your opponent does not see it. Hope chess is when you make a move, wait for what your opponent does, and then hope you can meet his threats. Players that play Hope Chess will never get very good because some threats cannot be met." |
HotFlow, in your original post you said, "Unless he planed to sac that pawn and had some counter in mind, but I doubt it." To me, this was the key mistake. If you looked one move ahead, saw that White could reclaim the pawn, and still wanted to take it for some reason that would have been slightly better. Loomis is trying to help the original poster avoid pitfalls like playing hope chess. Improving is the main goal of most people who post their games here for analysis, even if your primary goal seems to be somewhat different.
Dear Mr. Flow (if that is your real name),
"Hope chess" is not hoping that your opponent will make a mistake that you can take advantage of. "Hope chess" is ignoring the good moves your opponent has available to him.
Sincerely,
Loomis
I have no grudge at all. I was just trying to help out the original poster. Taking the pawn on e4 is well known in this opening and I simply didn't want him to walk away with poor advice.
Eric,
8 .... b5 and 9 .... Be7 looks like a fine continuation, however, a little conceptual understanding is also called for. If you look at the position after 8 c3 it is clear (to me, anyway) that it is white who is the most prepared for a big bust up in the centre. Black is required to castle asap. What you've shown is over-ambition and over-aggression (even if the position were not loaded with tactics). Attacks based on shoddy foundations are mostly doomed to failure. I'm not sure who said it first (it may have been me... my memory is in decline):
"The desire to attack is not enough, one should also have the better position!"
I believe the line I suggested was as good as any.
In your original post you didn't suggest any line, you suggested that a pawn was hanging that wasn't.
Later you suggest the following:
Bring out the white bishops to e6, since I suppose d4 will be played then bring the knight to d7. And the game looks good for both sides.
This seems to give white a good attack:
"Bring out the white bishops to e6, since I suppose d4 will be played then bring the knight to d7. And the game looks good for both sides."
In this ill-fated "pawn grab" variation I prefer 8...Be7 over 8...Be6 because it immediately prepares to castle, and with the e-file open and my opponent already castled that should be a top priority. I don't want my games to end like these games.
If 9.d4 Ne6 is fine and if 9.Nxf7 Kxf7 10.Qh5+ g6 11.Qf3+ Bf6! (but not 11...Bf6 12.g4!) and I think now Black has a winning game.
If Nf6 there, Bg5 and now your king is defending two minors. With Nf3-e5 coming and the second rook entering the center, black is not long for this world.
The bottom line is that it's been well known for many years that the pawn on e4 is not hanging. Recommending taking this pawn was bad advice that I wanted to steer the original poster away from. The fact you can't let this go is testament to your stubbornness.
My apologies, I had intended Nc3-e4 but was too hasty in typing.
I have no desire to rub salt in anyone's wounds. I don't know how many times I can say that all I wanted to do was make sure that good advice was received by the original poster. How your insistence on standing in the way of this is my fault, I'll never know.
