Please provide a better support for multiple ordinates. This was discussed in http://tex.stackexchange.com/questions/62291/can-i-draw-figure-3-y-axis-using-pgfplot for three y-axis. As noted in the manual the currently two axis are drawn on the top of each other and therefore user attention is required.
I think this should be improved such that
I would propose the following syntax:
\begin{axis}[domain=-5,10]
\addplot {x^2};
\addplot[custom ordinate] table {mytable};
\addplot[green,custom ordinate={name axis=A,ymin=0,restrict y to domain=-3:5}] {exp(x)}; %second axis is on the right of the box by default and has the same color as the first plot drawn for it, the axis should be named A
\addplot[blue,custom ordinate={use=A}] table {mytable2}; %plot mytable2 and use the ordinate called A, the color blue doesn't change the axis color, since this is determined by the first plot
\addplot[red,custom ordinate={axis shift=3cm,ylabel=axis 3}] table {mytable3}; % The third axis should be shifted to the right (from the right side of the box) by x cm by default, but you should be able to modify this via a key, say axis shift=3cm
\end{axis}
