1. Apart from representing Communication Skills, Marketing and Business etc. and being Significator of Astrology itself, Mercury represents many other things like Neurology, Brain, Memory. Neurological diseases are caused when Mercury is hemmed/aspected by Malefics but aspects from Jupiter and other benefic planets can save Mercury from such situation.
2. Mercury is exalted in Virgo and Debilitated in Pisces. So, we can understand that in Virgo it can make a great communicator or marketing person but what it will do in Pisces? Well, here also Mercury can make a person a great Author and Novelist but difference is that Virgo is a sign of Practicality, so in Virgo, Mercury makes a person communicate about practical things of life but Pisces is sign of imaginations, high ideals and spiritual values, here Mercury makes a person communicate about imaginary things, high spiritual ideals and values.
3. Mercury is also our logical thinking about what to do and what to avoid. That's where it is different from Jupiter. Jupiter is knowledge and Wisdom. Mercury is how to use that knowledge and wisdom.
4. As I said in one of the posts, to see if Mercury is working fine in your horoscope or not, just see how good you are at Calculating Numbers without any mechanical help. But if you are unable to do it, then don't think that your Mercury is doomed. It is just the base test.
5. When Sage Parashara decided about the gender of planets, he gave Sun, Jupiter and Mars - a Masculine Gender, Moon and Venus - a Feminine Gender and for Saturn and Mercury, he gave Neutral Gender. One of the reason for giving Saturn and Mercury as Neutral Gender was, Saturn is Lord of Justice who judges our deeds and actions and Mercury represents our Decision Making skills. For both these actions (judging and decision making), first you need to be neutral, then only you can decide which side of story is correct.
6. Last but not the least, we tend to worry so much about Jupiter, Saturn, Rahu and Ketu, but it is Mercury, Venus and Moon which we deal with on daily basis. Mercury is communications/speech, Venus is relationships and Moon is mental balance. These 3 planets impact our daily routine life, more than anything else.
Hope it was interesting.
Vishal S Saxena - Astrologer