There seems to be a change in the google spreadsheet publishing options. It is no longer possible to publish to the web as csv or tab file (see this recent post). Thus the usual way to use RCurl to import data into R from a google spreadsheed does not work anymore:
u <- "https://docs.google.com/spreadsheet/pub?hl=en_GB&hl=en_GB&key=0AmFzIcfgCzGFdHQ0eEU0MWZWV200RjgtTXVMY1NoQVE&single=true&gid=4&output=csv"
tc <- getURL(u, ssl.verifypeer=FALSE)
net <- read.csv(textConnection(tc))
Use the googlesheets package, a Google Sheets R API by Jenny Bryan. It is the best way to analyze and edit Google Sheets data in R. Not only can it pull data from Google Sheets, but you can edit the data in Google Sheets, create new sheets, etc.
The package can be installed with
The GitHub link above has a readme with usage details; there's also a vignette for getting started. And you also can install the latest development version of the package from that GitHub page, if desired.