So, you want to mine resources, sell them to a planet or a starbase, and become rich. Nothing wrong with that. The tutorial shows how to do it, if resources are plentiful. The problem is, if you are not going to exercise restraint, they won't be plentiful for long. (Note that the information in this guide does not apply to exotic matter, as it is governed by a different set of rules. You are encouraged to stripmine it.)
Every field in pardus has a resource value - a number from 0 to 500. The more there is, the more you are going to get. You will get ten times more stuff per collection from a field that is 500, than from a field that is 50. If a field gets too low, you can't harvest at all.
The fields regenerate once a day, by the amount that depends on the field value. The more stuff there is on a field, the more will be regenerated. A 450-resource field will generate 50 resources in two days; a 10-resource field will take weeks to generate the same. This is why most traders don't like stripminers very much.
A stripminer is somebody who collects resources until field values are low. The definition of "low" varies, but as a general rule of thumb, do not take a resource below 350, if you don't want to be labeled a stripminer, hunted, and chased away. You might be tempted to do that anyway, thinking that you can avoid detection. This might even work. For a while. And besides, it's not very smart even from a very egoistical point of view, and here's why.
A stripminer cuts the branch on which he sits. It doesn't take long to stripmine a sector, and then the delicious profits are gone, for a very long time. Pardus relies on APs - the farther you have to go to get your money, the worse off you are. Do the math if you don't believe me. In fact, you might find that trading offers bigger profits per AP, and it will usually generate much more goodwill towards you, but that's beside the point.
So, in conclusion, stripmining does not make economic sense from the point of view of the stripminer, and certainly not from anyone else's. It has all sorts of bad effects on sector economies, which I have not described; no wonder stripminers are not liked very much. In fact, stripmining is used in wartime to cripple enemy's economy... do you want to do such a thing near your home?
Also, don't forget that the non-agression agreements that we have with other alliances usually prohibit stripmining on the other alliance's territorry, since stripmining is recognized as an act of aggression.
Don't do it. It's not worth it.