A paper titled "Price Fluctuations and the Use of Bitcoin: An Empirical Inquiry" looks at various indicators which might be driving the bitcoin price.
From the abstract:
This paper empirically examines Bitcoin – one of the latest innovations in electronic finance. By focusing on price formation we discover that Bitcoin returns are driven primarily by its popularity and the transactional needs of its users. We also conducted a survey of merchants who have adopted this technology and model the share of sales paid for with this alternative currency. Particularly, we look at how company-specific characteristics, use of other payment methods and customers’ knowledge about Bitcoin interact with the proportion of sales attributed. The results presented here allow us to better understand the economic ramifications of this innovation.
The paper concludes that the popularity of Bitcoin itself is one of the factors driving the price. It also states that as newspaper articles mentioning Bitcoin increase and the number of people conducting a Google search for Bitcoin related keywords increase, so does the price.
A survey of merchants who accept bitcoin payments found that startups processed more sales paid with bitcoin than that of businesses which maintain a brick and mortar presence. In addition to this, the survey found that the more a customer knew about Bitcoin, the more likely it was for a merchant to process a bitcoin payment.
The 43 page paper, co-authored by Michal Polasik1, Anna Piotrowska2, Tomasz Piotr Wisniewski3, Radoslaw Kotkowski4 and Geoff Lightfoot5, is available for download as a PDF here.