The last time Mercury was in Pisces (January 31st) it turned retrograde at 3 degrees. On March 17th, it enters Pisces again. 0-3 degrees Pisces will be significant because they represent whatever started, but dissolved, when Mercury went Rx.
The question that wasn't quite asked may be answered. The discussion that was hinted at, then dropped, may be continued. The creative idea, the dream, the secret that you brushed against, may be fully explored. When Mercury enters Pisces, it will be time to pick up where you left off.
Mercury will also be approaching a conjunction with Neptune (at 6 degrees) exact on March 22nd. Neptune expands Mercury's facts into faith. Mercury gives focus to Neptune's dreams, but Neptune blurs Mercury's clarity. It can go either way. This suggests a buildup (from March 17th) to a moment of inspiration, belief or illusion. Your best bet is to consider issues that involve cold, hard logic (facts, figures) at risk of sliding out of focus. On the other hand, issues that involve creativity, empathy or spirituality can bloom.
If nothing else, you can use this influence to give your mind a break; consider different possibilities, meditate, escape. Sometimes the magic happens when you stop focusing and allows things to get blurry.
If you have planets/angles/Node (natal or Progressed) from 0-6 degrees Pisces, Virgo, Gemini or Sagittarius you'll feel this energy most strongly.