  Cryptocurrencies are a type of digital money meant to provide security and
anonymity while using cryptography techniques. Although cryptocurrencies
represent a breakthrough and provide some important benefits, their usage poses
some risks that are a result of the lack of supervising institutions and
transparency. Because disinformation and volatility is discouraging for
personal investors, cryptocurrencies emerged hand-in-hand with the
proliferation of online users' communities and forums as places to share
information that can alleviate users' mistrust. This research focuses on the
study of the interplay between these cryptocurrency forums and fluctuations in
cryptocurrency values. In particular, the most popular cryptocurrency Bitcoin
(BTC) and a related active discussion community, Bitcointalk, are analyzed.
This study shows that the activity of Bitcointalk forum keeps a direct
relationship with the trend in the values of BTC, therefore analysis of this
interaction would be a perfect base to support personal investments in a
non-regulated market and, to confirm whether cryptocurrency forums show
evidences to detect abnormal behaviors in BTC values as well as to predict or
estimate these values. The experiment highlights that forum data can explain
specific events in the financial field. It also underlines the relevance of
quotes (regular mechanism to response a post) at periods: (1) when there is a
high concentration of posts around certain topics; (2) when peaks in the BTC
price are observed; and, (3) when the BTC price gradually shifts downwards and
users intend to sell.
