I have had pretty good success making trades here. That said, the userbase (like Puca's) is limited and since you have to trade card-vs-card, it may be harder to find trades that work.
I have several cards that should see demand, but because it is hard to find the right trading partner, it makes it hard to make a deal.
PS: I am experiencing the same issue with non-responses. I have been made aware that if you leave a comment, it triggers the "You have messages" whereas a proposed trade does not. Leaving comments did seem to help me.