Quote from the Ad-
"GEM uses your Smart meter to track your usage everyday
and can tell you how much you have spent each half hour"
Now maybe I'm silly but as it turns out the data you get from GEM is actually 2 days old - so you can note down what appliances you use - then wait 2 days - then have a look at how much power it used....
Not really as useful as its made out to be...
Anyway, interested in others opinions, here is the link to the video:
Meet GEM - The Good Energy Monitor from Mercury Energy - Ad on Youtube