would love to trade PHR at cryptobridge, you guys should check it as an alternative to cryptopia.
It's not an alternative, volume on crypto-bridge is ridiculously low. It's nice exchange though.
It will take off. I think decentralized exchanges will be very busy over the next few years. Might be a good idea to get on them now.
That's a tricky one. Having too many exchanges can dilute trading volume, so it is important to add more exchanges at the right time.
That said, as far as I understand cryptobridge is an altcoin, and holders make a profit for each exchange done? Does that mean the price of bridgecoin would potentially impact trading on cryptobridge?
How can a large number of exchanges reduce the volume of trades

Usually volumes only increase!
Depends I guess. If people are "forced" to trade on a small number of exchanges, all the volume will be concentrated there. If you add other exchanges, new people might come in, but some of the trade from the existing exchanges might also move to the new exchange.
I am just a bit sceptical because I have seen coins with 5+ exchanges, and 3 or 4 of them had < 1 BTC volume, which seems a bit pointless.