There are traders that love to trade the news and that means that they actually are trading the volatility news releases is bringing, not the economic news in itself. Because markets sometimes have the tendency to react differently as expected when economic news are related.
However, when talking about online forex news, the economic calendar should not be the only thing to take into consideration. We're living in a world so interconnected due tot the Internet access that when somebody says something (central banker, member of a company's board, etc) interesting/important, then news channels and social media networks (Twitter, for example) amplify it and markets react extremely quick to such events.
The most important economic releases that moves currency markets, in the category of forex news, are the pmi's (services and manufacturing), jobs data (non-farm payrolls in the United States, claimant count in the United Kingdom, etc), consumer confidence levels, ISM (Institute for Supply Management) services and manufacturing in the United States, and, of course, inflation levels, with the favored tool to measure it being the cpi (consumer price index). These economic releases are watched by traders all over the world due to the fact that central bankers take them into consideration when setting the interest rates levels. And when trading currency markets, believe me, interest rates are the main driver for each currency.
Traders that fall into the category of trading only the online forex news related to the currency markets, are being called scalpers. This term refers to those traders going for smaller and quick profits, also known as intra day traders. For such a trader the economic calendar is a must as these are the times when markets are moving and in order to make a quick profit, even if a small one, you need to be there when the move occurs.
However, there are also the so called swing traders, and they can be assimilated as being the equivalent of an investor on the equity markets. They look for high impoact news like gdp releases/revisions and interest rate decision for entering/exiting a trade and they are usually trading higer time frames. But regardless if you're a scalper or a swinger, when trading the currency markets forex related news are something to consider.
