It doesn't matter how great your analysis is unless you can share it with others – easily. R Markdown and knitr make it easy to intermingle code and text to generate compelling reports and presentations that are never out of date. Combine R Markdown with packrat to ensure that your reports are reproducible day in and day out, no matter what other R packages you have installed.
The Next Generation of R Markdown
Jeff Allen, RStudio
Yihui Xie, RStudio
Packrat – A Dependency Management System for R
J.J. Allaire & Kevin Ushey, RStudio