Setting up author or address string variables in LaTeX - latex

Question

LaTeX is a wonderful language for writing documents. With the hyperref package and pdflatex, you easily generate documents with metadata, a nice feature to get your documents referenced right on the web.
I often use templates like:
\documentclass[11pt]{article}
\usepackage[pdftex, pdfusetitle,colorlinks=false,pdfborder={0 0 0}]{hyperref}%
\hypersetup{%
pdftitle={My title},%
pdfauthor={My name},%
pdfkeywords={my first keyword, my second keyword, more keywords.},%
}%
\begin{document}
\title{My title}
\author{My name}
\date{}
\maketitle
{\bf Keywords:} my first keyword, my second keyword, more keywords.%
My text is here...
\end{document}
So far, it's well. My question pops out from the example: is there a way to define string variables in the header so that they can be passed as arguments to hyperref and then to the frontmatter or to the text. Something like:
\documentclass[11pt]{article}
%-------definitions-----
\def\Author{My name}
\def\Title{My title}
\def\Keywords{my first keyword, my second keyword, more keywords.}
%--------------------------
\usepackage[pdftex, pdfusetitle,colorlinks=false,pdfborder={0 0 0}]{hyperref}%
\hypersetup{%
pdftitle={\Title},%
pdfauthor={\Author},%
pdfkeywords={\Keywords},%
}%
\begin{document}
\title{\Title}
\author{\Author}
\date{}
\maketitle
{\bf Keywords:} \Keywords %
My text is here...
\end{document}
This fails for the \maketitle part and for the hyperref metadata with ! Use of \Title doesn't match ! Argument of \let has an extra }.but also for including the keywords.

Answer 1

The correct template should look like:
\documentclass[11pt]{article}
%-------definitions-----
\newcommand{\Author}{My name}
\newcommand{\Title}{My title}
\newcommand{\Keywords}{my first keyword, my first keyword, more keywords.}
%--------------------------
\usepackage[pdftex, pdfusetitle,colorlinks=false,pdfborder={0 0 0}]{hyperref}%
\hypersetup{%
pdftitle={\Title},%
pdfauthor={\Author},%
pdfkeywords={\Keywords},%
}%
\begin{document}
\title{\Title}
\author{\Author}
\date{}
\maketitle
{\bf Keywords:} \Keywords %
My text is here...
\end{document}
Compiles fine and the metadata shows fine in the pdf reader.

Answer 2

Try using \newcommand{\Author}{My name} instead of \def.