Indentation of a block in beamer

beamer sets the paragraph indent to 0pt by default (in beamerbasemisc.sty). So, using \indent doesn't have any effect, nor does \hspace*{\parindent}. You can use \hspace*{20pt} though:

\documentclass{beamer}
\begin{document}

\begin{frame}
\indent ffffffffffffffffffffffffffffffffddddddddddddddddddd % No indentation
ddddddddddddddddddddddddddddddddd
dddddddddddddddddddddddd
\end{frame}

\begin{frame}
\hspace*{\parindent}ffffffffffffffffffffffffffffffffddddddddddddddddddd % No indentation
ddddddddddddddddddddddddddddddddd
dddddddddddddddddddddddd
\end{frame}

\begin{frame}
\hspace*{20pt}ffffffffffffffffffffffffffffffffddddddddddddddddddd % Forced 20pt indent
ddddddddddddddddddddddddddddddddd
dddddddddddddddddddddddd
\end{frame}

\end{document}

A 20pt paragraph indentation is the default setting for LaTeX (see latex.ltx).

Because I do prefer to have \indent work in beamer like it does in my article class (and others), I have the following in my preamble:

\renewcommand{\indent}{\hspace*{2em}}

This allows \indent to behave as I expect.