Would it be possible to provide a facility to upload data, in a similar way that an image can be uploaded?
For example, although small samples of data can be pasted into the question, it could be a useful facility to have a way of uploading a file containing data (with a size limit). I don't know if an equivalent to imgur would work, but this would be a nice alternative to providing a link to an external website (such as a dropbox file in your public folder) as it would be less likely to expire. It would also make the process of learning about statistics more complete for future readers of the question.
Expanding a little more on this idea, say the data can be uploaded to a particular question, and then accessed through a suffix like
Data Url for Question:
head section of the data (the first 5 lines and column headers) could be shown formatted by the site, similar to the way an image is displayed in browser.
Storing data in this way would be particularly helpful for software programs that are command driven. Users of
R for example could type the following to get access to the data referred to in the question:
dataSample <- read.csv("http://stats.stackexchange.com/questions/20921/data.csv")
This could also be a useful function to have for questions on other StackOverflow type sites.