About the credibility issue.
VGC only needs very, VERY basic accuracy. It relies on getting the numbers out faster, and having a community to openly discuss them. These are not a substitute for accuracy, they are different values entirely.
If you're a forum dweller interested in game sales, your pre-VGC option was to cobble numbers together from across the world, and in the case of the US, have only the top ten SKUs, released 2-7 weeks later. With VGC, you have new numbers every week and a big database and 1000 other fans dissecting everything. Better accuracy from NPD a month later cannot compete.
As VGC improved, it moved upmarket. If you're an investor, your old option was again to cobble together WW numbers and sit on your hands waiting for US numbers. Now if game X sells 60K, and VGC reports 100K, that's good enough if expectations were 250K. Add to that a community which quickly finds pertinent inaccuracies, monthly comparisons with NPD, etc, and you can form a feel for what you can trust. Better accuracy from NPD a month later cannot compete.
"I think people should define the word crap" - Kirby007
Join the Prediction League http://www.vgchartz.com/predictions
Instead of seeking to convince others, we can be open to changing our own minds, and seek out information that contradicts our own steadfast point of view. Maybe it’ll turn out that those who disagree with you actually have a solid grasp of the facts. There’s a slight possibility that, after all, you’re the one who’s wrong.