Besides all the uncommon events of 2020, Bitcoin finally passed 20,000 USD this year, and grabbed more attention about what is going on in cryptocurrency and what will happen next? So far, several researchers used social media data in their works and the role of public opinion, especially in the specialized forums on Bitcoin price, was proved. To have a better understanding of the discussions in Bitcoin specialized forums, in this thesis we studied the evolution of discussions in bitcointalk.org, as the main references of discussions related to Bitcoin over the past 10 years. We found 31 different topics in the forum by applying LDA topic modeling and categorized them into 6 categories: Future, General, Mining, Monetary, Regulations, and Technical. Our investigation on this work finds a relation between Bitcoin price and the sentiment polarity of selected categories of discussions in the forum.