I'm using \renewcommand{\familydefault}{\sfdefault} so that my entire document is in sans serif, but I'm getting peculiar results with regards to formatting.
I'm a rather sparse LaTeX user, but in the past I've always used \textbf{Super Important Text!} for bold text rather than what I've been told is obsolete; {\bf Important Junk} (which is what I first learned).
While I have that \sfdefault line in the preamble, \textbf{} is completely ignored while {\bf } is not. I suppose it wouldn't be the end of the world if the answer is that I just have to use {\bf }, but I'm assuming there's a reason you're not supposed to.
The closest solution I could find was Bold sans-serif font in LaTeX, but it dealt with section names rather than in text formatting.
EDIT: My apologies - after recreating the document bit by bit, it turns out \usepackage{charter} was causing this. The confusing part was that if I removed \renewcommand{\familydefault}{\sfdefault}, then normal boldface functionality was restored. It turns out \textbf wouldn't work iff both lines were in the preamble. Although I'm curious to know why this is, I don't need charter for the project I'm currently working on, so for practical purposes this issue has been resolved.
\documentclass{article}
\usepackage{charter} % If either of these two are removed
\renewcommand{\familydefault}{\sfdefault} % There is no issue
\begin{document}
\textbf{Not bold.}
{\bf Quite Bold.}
Also Not Bold.
\end{document}
Not Bold. Quite Bold. Also Not Bold.

\textbfis obeyed. Can you show a minimal example of code producing the issue? – egreg Nov 01 '12 at 00:40