Well everytime the forum has gone down for a few days the price does seem to go up for a bit
It's likely a coincidence or maybe sentiment turns positive when everyone is off the main feed.
maybe because everyone start trading some coins(thus mostly buying at first) instead of posting for their sig, this could be a reason
That does seem like a reasonable correlation, reduce posts and go and trade a few coins instead.
A variety of factors could determine it but if I was going by the results of a study in the economics section of the forum it would be because more people go to wikipedia to check what Bitcoin is and twitter posts increasing related to Bitcoin that causes a marginal blip in prices whenever the forums go down due to short term correlations well at least they used some calculations to back their arguments.
https://bitcointalksearch.org/topic/m.11460797Using Time-Series and Sentiment Analysis to Detect the Determinants of Bitcoin Prices
See
http://papers.ssrn.com/sol3/Papers.cfm?abstract_id=2607167Abstract:
This paper uses time-series analysis to study the relationship between Bitcoin prices and fundamental economic variables, technological factors and measurements of collective mood derived from Twitter feeds.
Sentiment analysis has been performed on a daily basis through the utilization of a state-of-the-art machine learning algorithm, namely Support Vector Machines (SVMs).
A series of short-run regressions shows that the Twitter sentiment ratio is positively correlated with Bitcoin prices. The short-run analysis also reveals that the number of Wikipedia search queries (showing the degree of public interest in Bitcoins) and the hash rate (measuring the mining difficulty) have a positive effect on the price of Bitcoins. On the contrary, the value of Bitcoins is negatively affected by the exchange rate between the USD and the euro (which represents the general level of prices). A vector error-correction model is used to investigate the existence of long-term relationships between cointegrated variables. This kind of long-run analysis reveals that the Bitcoin price is positively associated with the number of Bitcoins in circulation (representing the total stock of money supply) and negatively associated with the Standard and Poor's 500 stock market index (which indicates the general state of the global economy).