A long AdAge piece shows that at-home broadband penetration has reached a critical mass, and major portal firms are trying to exploit it by increasing both video content and video advertising opportunities. Parsing out the differences between the efforts of MSN, AOL and Yahoo, the portals are all seeking to figure out how advertising works in this new context (commercial pods interrupting content isn't well tolerated by web-spoiled viewers) and advertisers have yet to shift budgets marked for video ads to anyplace other than television.