A voting page on a crypto exchange is where people can vote (founders can vote too) with cash (the cost for one vote = 0.001 BTC) for their favourite coin (in our case DDX) to be listed on the said exchange/s.

I did not liked the fact that we had to wait (twice !! -- and it was actually delayed with about 3 months) to finish the pre-ICO round 2. This ICO final round I trust you Roberto that you won't let that shit happen again !

As for the two proposed listings, C-Cex (although not a well respected exchange) would be fine enough for DDX to be listed on Coinmarketcap ! Still, without Roberto pumping a couple BTC in voting DDX won't be listed.
On the other hand, if DDX will only be listed on SouthXChange will be worth just dust in the eyes of us investors because that will mean no DDX on Coinmarketcap (but only on some sites like Worldcoinindex blah blah) !!!