Note that, as stated by @Mbitr, you seem to be interpreting the decimal point wrongly. The reading on the Twitter entry is 12,15$ (12.15$ in the image), where the separator is a decimal point.

I tried to see where the exact figure came from for the sake of it. This site places the price for today-10 years at 11,86$, whilst this other one brings back the 12,15 $ mark (but as a summary for the whole of october 2012), and this other site sets the mark at 12,04$ per BTC. Not that there is much difference between them though.