Around Sept 2013, a few months before MtGox blew up. Those were the exciting times, the speculations and theories behind are they solvent, who is Satoshi, who is DPR? (the funniest was the company selling miners realizing that running the miners (Butterfly? I think) was more profitable then selling them, and they used prepaid costumers' money to do it) Those were the times!!!
Today although the return is higher (or the same) it is just boring... We haven't had a decent scandal in the last 6 months. It is all technicals nowadays...
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Edit for accuracy: Apparently my memory is shit. I did a search on ET and the earliest Bitcoin thread was from 2011 June and I already participated in it. So that was 6 years ago and no I didn't buy it. I also didn't buy NFLX, AMZN or TSLA. I was bearish on all of those....
I bet you would like to know what I am not buying today.
I heard about it and researched it way back near the beginning. I read several places that mining wasn't worth the cost of electricity so pretty much stopped worrying about it. Ugh.