This progression happens in every starting endeavor. 
It begins with nothing, and progresses.
Why the hyperbole?
Bitcoin is in beta, (I remind myself of this every time I re-balance my meager portfolio to keep no asset above 5%.)
It is still the early days, though Bitcoin is getting a bit overextended with all the current attention.
Its all good though, just yet another test which makes us stronger in an antifragile way.

Can we get an update on the graph in the OP?

So...  sell at US$1K until April?

No... you...

chart, I have not found a reason to adjust the plots of this Andrews Pitchfork and more reasons to leave it on.

we are back +1000$ 

I'm personally leaning toward the "revert to the trend" scenario, but suspect that it will get there mostly through time - rather than much greater price drops. Of course we could be seeing an acceleration of the trend with all the breakthrough acceptance BTC has achieved in the last month. If so I will be sad to let go of the current trend chart (even in exchange for a more aggressive line), as it has been very comforting to have next to my desk. But BTC keeps blowing my mind - and that is the name of the game - so I guess no reason to stop now.

You just need a new and improved chart next to your desk showing growth to $1,000,000 next year.    Hey, it is probably more accurate then the $1300 potential value for BTC that Bank of America somehow came up with last week!

Using all data from MtGox from bitcoincharts, the trend is 1 doubling every 120 days, 8x in a year, or 0.571% per day.  Also, the current expected value from the trend is $250.  In an equation this gives:

$ = 250*1.00571^{days from today}  
$ = 250*1.186^{months from now}
$ = 250*8^{years from now}

Only 8 x 250 = $2000 next December.  But I think the complete change in trust the past few month is a 1-time bonus that shifts the trend up without affecting the long-term growth rate.  If $900 is fair right now, then the equation is

$ = 900*1.00571^{days from today}  
$ = 900*1.186^{months from now}
$ = 900*8^{years from now}

or 8x900 = $5,600 next December.

The theoretical limit is $1 million per coin based on the world money supply.

Imagine the influx if some banks want to hold it as an asset.  All that Fed money buying up toxic assets has got to go somewhere.  It has not been going to M2 which has been stable.  They're just shoring up and dumping their toxic waste.  The bank crime against taxpayers is on going, and people act confused as to why inflation is not higher.  Banks are keeping it, not distributing it.

An orderly trend is just way too boring! 

I guess boring is predictable though and there is some comfort to be had in that for sure.  Strange as it might sound, most people would probably prefer a more orderly progression.  Unpredictability is hard for most to stomach.

The accelerating part of the S-curve is only ever exponential growth. It just starts to feel "vertical" to us humans at some point. It doesn't ever go faster than exponential growth (in the ideal curve). The first half is exponential growth and the second half is logarithmic leveling off.