There still are a few things they do well. For example, their Finance feature is among the best in class of financial information (IMHO).
Except that their charts show the price of the stock/fund without adjusting for dividends, i.e. there is no way to graph "adjusted price" or "growth of a $1000 investment." So, when a mutual fund makes a big capital gain payout, which has no economic significance (they hand you a check for $X per share and the share price drops by $X), the chart shows a big dip. If you try to chart two securities together to compare them it is totally misleading because of the economically meaningless dips when there is a dividend or capital gain payout. They have the data to do this right, it is displayed as the "Adj Close" in the "historical prices" table, but they don't make it available in the charts. When they've been doing something that dumb for over a decade in spite of complaints, how can you trust anything they do?