Unless something has happened to drastically alter EEG analysis since last I checked, this is meaningless with one electrode. You need at least one other specifically to measure eye/muscle movement, etc.
You can remove artifacts like eye and muscle movements with prepossessing, not as well as with electrodes, but still.
I'm more worried about electrode connections and electrode quality in these amateur EEG applications. You also want high quality active electrodes if you take EEG outside laboratory. I'm also skeptical about these dry skin electrodes (no alcohol scrubbing and conductive paste). NeuroSky devices are surprisingly cheap. I would be very interested to know how well they work in practice.