Wikipedia - The biggest free encyclopedia includes lots of information about binary option, trading, all assets, strategies and much more. It could be very useful for you to read this information.
Google Finance - the biggest search engine in the world provides plenty of financial information, charts, recent changes of many assets, latest news and others.
Reuters - The biggest news portal for business, economy and finances.
WSJ - the official website of Wall Street Journal, one of the useful sites with news and information about trading.