user2307: According to wikipedia in the main line of the Queen's Gambit Accepted White's 3rd move is: 3.Nf3:


[FEN ""]
1. d4 d5 2. c4 dxc4 3. Nf3


Doesn't that pretty much turn the opening into a real gambit? Black can now hold on to the c-file pawn since the usual trap (with Qf3) is no longer possible and b4 can be safely played by Black to prop up the c-file pawn.

user2005: Another reasonable continuation for white after 3. ... b5 is:
[fen ""]

1.d4 d5 2.c4 dxc4 3.Nf3 b5 4.a4 c6 5.e3

This transposes into a position more commonly reached via the Slav move order.  1.d4 d5 2.c4 c6 3.Nf3 dxc4 4.e3 b5 5.a4.
Here you can find a lot more example games to look through.  But still Black does not hold onto the pawn and instead gives it back.  The most standard continuation here is:
[fen ""]

1.d4 d5 2.c4 c6 3.Nf3 dxc4 4.e3 b5 5.a4 e6 6.axb5 cxb5 7.b3 Bb4+ 8.Bd2 Bxd2 9.Nbxd2 a5 10.bxc4 b4

White has recovered the pawn.  Stockfish rates this position as a clear advantage for white (+1.23), though Shredder's grandmaster database has it dead even with white only doing well after 11.Ne5 and with black doing better after Stockfish's suggested 11.Bd3.  So it seems that white has the advantage here but that black has good practical chances.

user2042: 
Doesn't that pretty much turn the opening into a real gambit?

No.

Black can now hold on to the c-file pawn since the usual trap (with Qf3) is no longer possible and b4 can be safely played by Black to prop up the c-file pawn.

No he can not. White will regain the pawn and get huge advantage.
Here are the most relevant lines, the rest can be easily found with an engine:
[fen ""]

1.d4 d5 2.c4 dxc4 3.Nf3 b5? 4.a4 c6 5.axb5 cxb5 6.b3 cxb3 ( 6...Be6 7.bxc4 Bxc4 ( 7...bxc4 8.e4 Qc7 9.Qa4+ Qd7 10.Bxc4 ) 8.Na3 Qc7 9.Nxc4 bxc4 ( 9...Qxc4 10.e3 Qc6 11.Ne5! Qb6 12.Qb3+/- ) 10.Qa4+ Nd7 11.e3 c3 12.Bb5 e6 13.Ne5 Ngf6 14.Bc6 Rd8 15.Qxa7+/- ) 7.Qxb3 Qb6 8.e3 b4 ( 8...Bd7 9.Ne5 e6 10.Nxd7 Nxd7 11.Qxb5+/- ) 9.Qd5! Bb7 ( 9...Qb7? 10.Bb5+!+- ) ( 9...Nc6 10.Ne5+-) 10.Bb5+ Bc6 ( 10...Nc6? 11.Ne5+- ) 11.Ne5+-

Best regards.

2307: <p>According to <a href="http://en.wikipedia.org/wiki/Queen%27s_Gambit_Accepted" rel="nofollow">wikipedia</a> in the main line of the Queen's Gambit Accepted White's 3rd move is: 3.Nf3:</p>

<pre>
<code>
[FEN ""]
1. d4 d5 2. c4 dxc4 3. Nf3
</code>
</pre>

<p>Doesn't that pretty much turn the opening into a real gambit? Black can now hold on to the c-file pawn since the usual trap (with Qf3) is no longer possible and b4 can be safely played by Black to prop up the c-file pawn.</p>
 2005: <p>Another reasonable continuation for white after 3. ... b5 is:</p>

<pre><code>[fen ""]

1.d4 d5 2.c4 dxc4 3.Nf3 b5 4.a4 c6 5.e3
</code></pre>

<p>This transposes into a position more commonly reached via the Slav move order.  1.d4 d5 2.c4 c6 3.Nf3 dxc4 4.e3 b5 5.a4.</p>

<p>Here you can find a lot more example games to look through.  But still Black does not hold onto the pawn and instead gives it back.  The most standard continuation here is:</p>

<pre><code>[fen ""]

1.d4 d5 2.c4 c6 3.Nf3 dxc4 4.e3 b5 5.a4 e6 6.axb5 cxb5 7.b3 Bb4+ 8.Bd2 Bxd2 9.Nbxd2 a5 10.bxc4 b4
</code></pre>

<p>White has recovered the pawn.  Stockfish rates this position as a clear advantage for white (+1.23), though Shredder's grandmaster database has it dead even with white only doing well after 11.Ne5 and with black doing better after Stockfish's suggested 11.Bd3.  So it seems that white has the advantage here but that black has good practical chances.</p>
 2042: <blockquote>
  <p>Doesn't that pretty much turn the opening into a real gambit?</p>
</blockquote>

<p>No.</p>

<blockquote>
  <p>Black can now hold on to the c-file pawn since the usual trap (with Qf3) is no longer possible and b4 can be safely played by Black to prop up the c-file pawn.</p>
</blockquote>

<p>No he can not. White will regain the pawn and get huge advantage.</p>

<p>Here are the most relevant lines, <strong>the rest can be easily found with an engine:</strong></p>

<pre><code>[fen ""]

1.d4 d5 2.c4 dxc4 3.Nf3 b5? 4.a4 c6 5.axb5 cxb5 6.b3 cxb3 ( 6...Be6 7.bxc4 Bxc4 ( 7...bxc4 8.e4 Qc7 9.Qa4+ Qd7 10.Bxc4 ) 8.Na3 Qc7 9.Nxc4 bxc4 ( 9...Qxc4 10.e3 Qc6 11.Ne5! Qb6 12.Qb3+/- ) 10.Qa4+ Nd7 11.e3 c3 12.Bb5 e6 13.Ne5 Ngf6 14.Bc6 Rd8 15.Qxa7+/- ) 7.Qxb3 Qb6 8.e3 b4 ( 8...Bd7 9.Ne5 e6 10.Nxd7 Nxd7 11.Qxb5+/- ) 9.Qd5! Bb7 ( 9...Qb7? 10.Bb5+!+- ) ( 9...Nc6 10.Ne5+-) 10.Bb5+ Bc6 ( 10...Nc6? 11.Ne5+- ) 11.Ne5+-
</code></pre>

<p>Best regards.</p>
