Today, the sources of whatever information you read, even from the most credible sources, are obscured. Whether it is CNN or a peer-reviewed journal article, the most information you will get about the author is a name, a picture, and maybe a bit of their publicly available data.
With Web of Trust, the level of trust you should assign to an author, and by extension the information, can be instantaneously computed by adding up your own trust references.
If I assign my trust responsibly, and you assign your trust to me, then everyone I trust is by extension trustworthy, and the information metadata can reflect this.
If you don't think I assign my trust responsibly, then you can remove me from your trust circle, and my assigned trust will become irrelevant.
It's not a perfect system, it's vulnerable to attacks, it requires eternal vigilance, but it's the best we've got going for us today, IMO.