The Yahoo home page is a spammy disaster. Why would any user or investor think it was going anywhere?
Just look at the google home page to get a sense of how to build trust with users. It's not trying to trick you into clicking a sponsored link, not wasting your CPU on huge banner ads.
I would have to be paid $1K per year to switch to a yahoo email account, and I'm not even sure I'd be happy with the offer.