I think a big part of the problem is that, were Yahoo! to enter the phone game now, they'd be years behind their competitors. iOS, Android, BlackBerry, and Windows mobile are all pretty established, and could all easily out-maneuver a new competitor. Second, I don't think she would really move into a market that Google is already working in by introducing competition for Android.
Yahoo! needs to find some untapped market need and hit it HARD. Unfortunately, phones are probably not that need.
Per the GGP post, they can use Android, they wouldn't be competing with it. They can leverage their market position to create an additional Android app marketplace, or produce a suite of apps that create a Yahoo! integrated experience on other Android devices, whether they distribute these in their own store or someone else's. Android manufacturers already exist, establish a relationship with them and they can start churning out Yahoo!/Android devices in addition to their Google/Android B&N/Android and Amazon/Android devices. The device manufacturers are competing with each other and Apple for the market. They can be promiscuous with companies seeking to create X branded Android devices. They get to rely on their existing production infrastructure and design database, and they get paid by Brand X to create a custom design, it's not out of pocket for them.
The competition would be with the Google/Amazon branding, but Yahoo! already has a relationship with millions of customers, many of whom already own Android devices. Give them better Yahoo! integration into their existing devices + the future option of migrating to a Yahoo! branded device.
Ah yes, that makes sense. I'm not terrific at business sense, thanks. I had not considered that targeting existing Yahoo customers doesn't necessarily cannibalize Google's customers, since they're clearly not jumping to move to gmail, are they?
I'm not the person you are responding to, but I do think the idea of a Yahoo Phone isn't a winner. Mostly because phones are basically fashion items at this point. Can you imagine anyone being impressed that you have the latest Yahoo phone? Me neither.