The device connects to local WiFi. If it can't connect, it goes into Access Point mode and allows you to connect directly to it, search for local networks, select one, and enter the password. This functionality comes from tzapu's WiFiManager.
Future Plans/Wish List:
Filter Readings. Occasionally there are low/erroneous readings. Sampling at a higher frequency and calculating an average or median value to be uploaded might help.
Add a setup button. Right now, if Pin 13 is grounded, WiFi is reset and it goes into Access Point mode where you connect to you to change network settings. Connecting a button that can be pressed with a paperclip would be nice.
Add more configuration and upload options. Using the Thing/ESP8266 as an Access Point, it would be nice to be able to change the logging interval and data.sparkfun keys. There could also be other ways to share data, including Blynk or dweet.io (example project). Other possibilities: xively, grovestream, thingspeak, Twitter + IFTTT.