Font Awesome supported in emojifont
emojifont is available in CRAN, you can use the following command to install it.
install.packages("emojifont")
An example of using emoji font in R plot is showed below:

More examples can be found in the post and online vignette.
I found FontAwesome is quite interesting especially in technical world. In emojifont (version >= 0.3), I have packed the Font Awesome. So that we can use this fancy font in both base and ggplot2 graphics.
load.fontawesome()
set.seed(2016-03-09)
fa <- fontawesome(c('fa-github', 'fa-weibo', 'fa-twitter', 'fa-android', 'fa-coffee'))
d <- data.frame(x=rnorm(20), 
                y=rnorm(20), 
                label=sample(fa, 20, replace=T))
ggplot(d, aes(x, y, color=label)) + 
    geom_text(aes(label=label), family='fontawesome-webfont')+
    xlab(NULL)+ylab(NULL)

Have fun with emojifont.
https://twitter.com/ma_salmon/status/706490090609106944
