Why don't you simply send to Google trends the names of the companies that you are interested in. It has an excellent corpus of news articles, and if you tick "headlines" it even labels all the significant events for you! E.G. http://www.google.com/trends/explore#q=apple%20computer

and then compare with the 5 year stock price at https://www.google.com/search?hl=&q=NASDAQ+AAPL

Question for you: Why are there peaks in interest without any associated News Headlines?

December & January are traditional 'buy months', I think.

Good answer Demetris. Any other factors anybody?

There could be random fluctuations also. (random walk, stochastic process) Markets during time itervals without relevant information can produce patterns that seem abnormal, but they are normal. (heavy-tailed distribution)

So we know that PR in the newspapers affects interest (as measured by searches). Presumably the other non-randomness peaks in interest and possibly price are caused by events that do not make company headline news. E.g., insider information, suppressed bad PR, knowledgeable-person information such as news in associated industries (earthquakes affecting semiconductor prices), fickle stockholder sentiment and decisions, trader habits, buy/sell algorithms...

Also there is bad, neutral and good press...

Balázs: You will notice that there are many untagged and unexplained peaks in the Google trends. Nevertheless, news does generally generate known interest. How does known interest affect stock price? Are there correlations between the two graphs I posted above?

Sorry for the slow communication...

It is an interesting question. Nor search interest neither stock price is stationery - maybe if we observe changes in both time series, they will correlate in absolute value. (Increasing interest may indicate both upward and downward price changes, so taking absolute value is necessary.)