Copper is a most important industrial input, used globally in everything from computer manufacture to house building. Because it is a refined product, it can be standardised - the copper traded on Chicago exchanges is essentially the same as that traded on the London Metals Exchange. These factors mean that copper can be used as a proxy for global industrial sentiment, and it is currently trading close to an important support/resistance level.
The decline since July is in line with a the performance of many risk assets - shares, currencies - over the same period. Note the action around the $3.03 (USD per lb) price level. With copper hugging the support/resistance (green) line , the near term direction is not clear. However, the next significant move away from this level could set the direction not only for copper, but many other assets that are affected by global industrial sentiment.
There are still extremists in the charts vs fundamentals arguments. Some argue that charts are a form of "voodoo", and that fundamental analysis is the only rational basis for trading and investment. Technical analysts typically lean on the idea that all that is currently known about a share, commodity or currency, is reflected in the price - that price action is "primary evidence".
Many traders sit somewhere between the extremes, using a combination of fundamental and technical analysis. Those who do take note of charts could keep a close eye on the next move for copper.