It's speculation using historical trends of varying lengths to try to find some kind of usable pattern in the price action.
At any given time, an ongoing trend is more likely to continue than not (thus the old investment adage, "The trend is your friend"). So there is a lot of interest in identifying what "the" trend is. People present different trends and try to explain why they think the price is tracking their trend and what might have triggered that trend. Trends can be multilayered; there can be trends within trends (within trends).
In this case we had a remarkably steady, clear trend of fast exponential growth from mid-January until April. Just a few weeks after it started, I asked
what might happen if it were to continue, then in mid-February I extrapolated that trend to predict
$100 by the end of April even though a bitcoin was only $25 at the time.
Then the bubble started it onto double-exponential (exponential growth in the
rate of price growth, rather than just exponential growth in price) and went way above the trendline, exceeding even my incredibly bullish predictions that were laughed at. That was great for a while, but then the bubble popped and the price fell quite a ways below the trendline. What now?
Well the question arises: Are we still following that same trend? Right now we are well below the trendline, so it could be argued the technical damage from the bubble broke whatever fundamental reason that was driving the exponential growth since mid-January. However, it can alternatively be argued that it is pointless to say we are no longer tracking the trendline when we haven't been below the trendline any more than we've been above it (the green and red regions in the first graph are about equal). It could be argued that we should at least wait until we've been below the trendline for a lot longer than we were above it before we start to wonder if the 2013 exponential growth trend has been broken.
Moreover, if we go with the assumption that the trend will continue (since "the trend is your friend"), then the fact that we've spent this much time this far below the trendline indicates we are likely to go higher in the coming weeks. Conversely, if we spend a lot more time below the trendline, it would give reason to start to doubt the 2013 trendline, perhaps reverting to the historical trendline posted above.