acronymscapitalizationsmall-capstypography
The recommended way of typesetting acronyms is using small caps, e.g.:
This technique is called Remote Procedure Calling or {\scshape rpc}.
However, if the acronym occurs at the beginning of the sentence, would you capitalize its first letter or not?
{\scshape rpc} is the name of this technique.\\
{\scshape Rpc} is the name of this technique.
Which one would be most appropriate and why?
Not really a compelling rationale, but I would go with method 2 because that's what The Economist does:
(The Economist, November 6th 2010)
If you don't mind to create a new command \acfoot and use it instead of \ac in these cases, here is a solution:
\documentclass{report}
\usepackage{acronym}
%\usepackage{footnote}
\newcounter{mycount}
\newcounter{savefoot}
\makeatletter
\newcommand\acfoot[1]{%
\begingroup%
\setcounter{savefoot}{\value{footnote}}%
\setcounter{footnote}{\value{mycount}}%
\addtocounter{footnote}{-1}%
\renewcommand\@makefntext[1]{}%
\ac{#1}%
\setcounter{footnote}{\value{savefoot}}%
\endgroup%
}
\makeatother
\begin{document}
\begin{acronym}[ABC]
\acro{ABC}{Alphabet\protect\footnote{this works}\setcounter{mycount}{\value{footnote}}}
\end{acronym}
The \acfoot{ABC}\footnote{this works, too}.
\end{document}
Output:
Note that you can also define a new command \acrofoot
\newcommand\acrofoot[3]{%
\acro{#1}{#2\protect\footnote{#3}\setcounter{mycount}{\value{footnote}}}%
}
and use it instead of \acro giving the footnote text as the third argument:
\acrofoot{ABC}{Alphabet}{this works}
This solution works better, but has its limitations (for example you can't use numbers in acronym definitions):
\documentclass{report}
\usepackage{acronym}
\usepackage[colorlinks]{hyperref}
\newcounter{savefoot}
\makeatletter
\newcommand\acfoot[1]{%
\begingroup%
\setcounter{savefoot}{\value{footnote}}%
\setcounter{footnote}{\value{#1count}}%
\addtocounter{footnote}{-1}%
\renewcommand\@makefntext[1]{}%
\ac{#1}%
\setcounter{footnote}{\value{savefoot}}%
\endgroup%
}
\makeatother
\newcommand\acrofoot[3]{%
\newcounter{#1count}\acro{#1}{#2\protect\footnote{#3}\setcounter{#1count}{\value{footnote}}}%
}
\begin{document}
\begin{acronym}[ABC]
\acrofoot{ABC}{Alphabet}{\url{http://abc.example.org}}
\acro{XYZ}{The End}
\acrofoot{Foo}{Bar}{\url{http://foo.example.org}}
\end{acronym}
The \acfoot{ABC}\footnote{this works}. Also see \ac{XYZ} and \acfoot{Foo}.
\end{document}
Output:
The trick is to define a new counter for each \acrofoot and use that one for numbering footnotes.
Best Answer
Don't use capitals in this case. Quoting Hedrick, Fine Points of Typographic Usage: