if you mouseover you will see thats the difficulty

i am not able to get the BTC difficulty because there is no ABE block explorer with API
And strangely, you can't get the difficulty for LTC after December 20, 2013, either.
On the v2 charts what the yellow line represents? If I hover the mouse over it, it doesn't show an explanation.
Tip for either the v1 or v2 charts: the ability to to have a clear reading of the actual price in a dedicated spot on the main screen, like on any trading chars, Yahoo Finance, BitcoinCharts, etc.
Keep goin'!