Welcome to the Newschoolers forums! You may read the forums as a guest, however you must be a registered member to post. Register to become a member today!
Yes, of course you can say both, but you would be wrong. For example:
"How are you doing?"
"I'm doing good."
So you're actively engaged in charitable work, at this very moment? The correct response is "I'm doing well" or "I'm well, thanks."
We have certainly learned to not believe everything we read, and this is no exception. Taking one's facts from a "quick and dirty" guide may be an indication that they are not of the highest quality. In general, yes, that website does have a valid point that "good" CAN be a correct response to a greeting. An example would be "How are you?" Good can be appropriate here, if certain things are inferred. However, "well" works as well. In the case of "How are you doing?" well is the only correct response, not good. Be safe, and use "well" for all responses.
To think of it a different way, take the example of "How are you doing?" To reply "I'm good" infers that you are in fact answering "I'm doing good," hence the example of being actively engaged in charitable work. To offer one last example, think of the questioner asking "How are you?" To this one could reply "I'm feeling good, thanks." Good would be the way one is feeling, and can sometimes be inferred without being stated, hence your example being correct to some degree.
If you want to approach this from a different angle, think of Good being the equal of Bad, and conversly Well being the equal of Poorly. Would you ever reply "I'm doing bad?" No, of course you would reply "I'm doing poorly."
To get back to the original topic, the difference between less and fewer is another thing that stands out to me. It seems most people use these incorrectly.