I think OP's trendline (the one we're all following lately) sucks to begin because it's drawn based on one part of it touching on a giant wick of a candle (SR october crash), which skews it greatly. Given this detail, the action where we are currently trading right on top of this trendline is very weak.
The tangent points on daily chart are:
4 days bottoms in Jan 2013
1 day in Oct 2013 (yep, the SR crash overshoots the trendline by a whopping $2)
1 day in April 2014 ($340 crash)
2 days in May 2014 (trendline test / fake out)
1 day in June 2014 ($538 bottom yesterday)
That is five seperate distinct periods when this trendline was tested, including one freak event, that many Bitcoin holders believed entailed a Bitcoin armageddon. I would suggest that this trendline is
a. Valid
b. Very significant
I agree that the action since the $538 bottom is woefully weak and indeed suggests that $538 wasn't the bottom. Should there be any further strong selling pressure over the next few days then Bitcoin will crash right through that 'trendline' at which point we will see first hand how important that trendline is or isn't.