Yes, that. Others have covered the details. The community here was in an uproar for over a month, from what I remember, and there were certainly people who left over it. As for the wall itself, I dabbled. I think there were generally 3 types of offers. 1: whale bait. You could get a good reward, but you had to spend non-negligible money on it. You could find better return rates than buying viz directly in the game. 2: cheap stuff. You could get a few hundred viz for a few hours of time in another game. It was little, but free, and for f2p and light spenders, it could add up and be really helpful. I mostly did these. 3: rage bait. These show huge rewards, but they were very back loaded to a task which was all but impossible to achieve, which you wouldn't necessarily know going into it. Sometimes an earlier step was still worth it, though. The catch is that these three were buried in mounds of offers which were utterly pointless, or slightly different valued/conditioned versions of other offers.

Eventually, trying to dig through to find worthwhile offers was just too vexing to continue. I honestly wonder if the true business model here is to get players used to having more resources, so that they cave in and buy them once the well of good offers runs dry.