Benefiting advertisers and benefitting Reddit are really the same thing. We can't please investors without building a long-term, sustainable business; we can't build a long-term, sustainable ads business without advertisers being happy with our product.

> CPMs should have gone down, not up, since your inventory was expanded meaning same demand for expanded supply.

This really depends, there's more supply available to you, but you're potentially competing against more advertisers as well. e.g. if, for example, there's high overlap between visitors to /r/jerky and /r/dota2 you might see increased CPMs, if there's not other advertisers competing for your same inventory you'd see lower CPMs.