I'm glad you like the interface ThatDGuy. It's still very rough around the edges, but the data is solid.
You are also spot on correct when saying you will be able to set your own personal custom percentage increases in those time frames.
Real Wold example: lets say you invest a lot of money specifically on Bitstamp. You don't really care about daily fluctuations but would like to know if there is a massive deviation on the 7 day price. You would then click "Activate alert" next to "7 days" on the Bitstamp graph.
The next page will then show you a form like this
When the BTC/USD on Bitstamp change by [ ]% alert me
You'll be able to choose a percentage that fits your needs.
In "My Account" you'll have a "My contact preferences" which will look like this
[x] Contact me via email [___________]
[ ] Twitter direct message this user [___________]
[x] SMS this number [___________]
[ ] Send a push message via pushover.net using this user key [___________]
Hope this explains it a bit better
