Check out the update in the notes section 2014/12/21/dynamic-pages-with-gohugo.io/.

Update 29. Jan. 2016:

Renamed the topic to Data-driven content because better wording :-)

Update 8. Feb. 2015:

The parameter --ignoreCache has been added to ignore the read from the cache but writing to the cache is still happening.

getJSON and getCSV are now variadic functions. You can submit multiple parts of an URL which will be joined to the final URL. Example:

{{ $id := .Params._id }}
{{ $url_pre :=  "http://localhost:3000/db/persons/" }}
{{ $url_post := "/limit/10/skip/0" }}
{{ $gistJ := getJSON $url_pre $id $url_post }}

For getCSV the separator argument has been moved to the beginning of the function.