One of the great things about knitr is its flexibility.  Here I set knitr up to publish to Wordpress.
I will then use RWordPress to publish the output automatically.   

I will base the wordpress format on the github-flavored markdown format.  I change the markup for output and source-code to use the nice codeblocks provided by the syntax highlighter plugin.  I also specify that images should use the html markup instead of github markup, and I will take advantage of knitr support for imgur to upload and host the image files automatically.   




[code lang='r']
render_gfm()
opts_knit$set(upload = TRUE)
knit_hooks$set(output = function(x, 
    options) paste("[code]\n", 
    x, "[/code]\n", sep = ""), 
    source = function(x, 
        options) paste("[code lang='r']\n", 
        x, "[/code]\n", 
        sep = ""), plot = hook_plot_html)
[/code]



Now we write some code chunks in this markdown file:

[code lang='r']
## a simple
#   calculator
1 + 1
[/code]
[code]
## [1] 2
[/code]
[code lang='r']
## boring random
#   numbers
set.seed(123)
rnorm(5)
[/code]
[code]
## [1] -0.56048 -0.23018  1.55871
## [4]  0.07051  0.12929
[/code]



We can also produce plots which are uploaded to imgur.com:

[code lang='r']
library(ggplot2)
qplot(hp, mpg, 
    data = mtcars) + geom_smooth()
[/code]
<img src="http://i.imgur.com/YfwwX.png" class="plot" />
[code lang='r']
ggpcp(mtcars) + 
    geom_line()
[/code]
<img src="http://i.imgur.com/udkrA.png" class="plot" />




We can then post the result using RWordPress:

[code lang='r']
require(RWordPress)
text = paste(readLines("wordpress.md"), 
    collapse = "\n")
title = "Using knitr and RWordPress to publish results directly from R"
newPost(list(description = text, 
    title = title), publish = FALSE)
[/code]



Above we specify publish = FALSE which will make the post upload as a draft where we can preview it.  To publish directly we could omit that command.  Giving a title is intuitive. Note that we have to read the text in and substitue newline characters for line-breaks.   

Note that this requires setting the login options securely in .Rprofile, for example:
[code lang='r']
options(WordpressLogin = c(userid = "password"), 
    WordpressURL = "http://www.yourdomain.com/xmlrpc.php")
[/code]




It would be nice to use the uploadFile function from RWordPress to host the images, but that seems to be giving me trouble at the moment.