*What's your secret for massive gains during a pump in the cryptocurrency market.
I would definitely share the secret if I were the owner of huge profits from the pump, as you say. 
I suppose the secret could be the following: buy cryptocurrency before the pump and sell as soon as the pump starts.
*Are pump signal announcements legit for investors who want to take advantage of the current market trend?
I don't think anyone will share real pump signals that are created for "internal" use. Sharing a pump signal means sharing your profit.*What could possibly be the gains of pumps for any new or old cryptocurrency like Bitcoin?
Pumps are only beneficial for the organizers of this, and for cryptocurrencies this only gives a decrease in trust after a short-term increase in interest due to a jump in price.