Beeminder?

;; Totally untested

(defvar clarissa/beeminder-user "example" "Username for Beeminder service.")
(defvar clarissa/beeminder-token "1234" "Token - get this from https://www.beeminder.com/api/v1/auth_token.json")
(defun clarissa/beeminder-post (goal datapoint)
  (interactive "MGoal: \nMData: \nMToken value: ")
  (let ((url-request-data (json-encode `((value . ,datapoint) (auth_token . ,clarissa/beeminder-token))))   
        (url-request-method "POST")
        (url-request-extra-headers '(("Content Type" . "application/json")))
        (url-mime-encoding-string "identity"))
    (condition-case nil
        (url-retrieve-synchronously
         (format "https://www.beeminder.com/users/%s/goals/%s/datapoints.json" clarissa/beeminder-user goal)))))
(defun clarissa/beeminder-org-update ()
  (interactive)
  (when (org-entry-get "GOAL")
    (clarissa/beeminder-post (org-entry-get "GOAL") (or (org-entry-get "POINTS") (read-string "Points")))))
(add-hook 'org-after-todo-state-change-hook 'clarissa/beeminder-org-update)