These constant updates on the stock market are worse than useless. The fact that the market is up 0.4% on a given day is utterly meaningless to the vast majority of people. The stock market's daily, and even weekly, drift is no indication of the direction of the market, let alone of the economy. Even a relatively large move in the market, say a rise or fall of 3% in one day, is not meaningful. There is nothing that any intelligent person can or should do in response to it, nor does it change anyone's life.
Reporting the Dow is, at best, a colossal waste of time. At worst, such reports create paranoia and fuel speculation. People who listen to the news, with its moment-by-moment reporting on stock values, could reasonably infer that these reports mean something. The Dow is down -- the economy must be in trouble! The Dow is up -- things must be improving! But that is not true. The Dow is up 0.4% today as a result of random drift, not because "bargain hunters are snapping up shares," as ABC reported.
Worst of all, the reporting of the market's small random drifts encourages people to speculate. The true value of stocks, over the long term, is based on the value of the businesses. More specifically, the value of stocks is based on the dividends that they will pay. Therefore, the value of a stock does not go up or down on an hourly basis, absent some important event, e.g., Merck's latest drug obtaining FDA approval. In any market, however, there will always be an element of speculation as well, people who buy solely for the purpose of finding a greater fool who will pay more. They do not care what the stock is worth, only what others think it is worth. Focusing on ultra-short term fluctuations in the market encourages people to focus on what the market will bear, not on the value of what is being traded.
Finally, although this is really beside the point, the Dow is a poor measure of the value of stocks, as it takes into account just 30 large companies. If you need to measure the value of the stock market, look to the S&P 500 or the Wilshire 5000, which take into account the broader market.