The old My Yahoo showed me mail coming in from Gmail, Outlook
Express and Yahoo. How do I get My Mail in the new My Yahoo? I
can't get it from "add content".
The Yahoo webmail interface is gotten to by clicking the envelope icon
in the upper left corner:
http://rednoise.x10host.com/temp/yahoo1.png
Some webmail services allow you to retrieve mail from other hosts such
as Google. I don't remember if Yahoo is one of those, but if it is, it
might tell you that mail has arrived from that other host.
I'm sorry, but despite what you say, I just don't believe that Yahoo
was ever aware of what Outlook Express is doing on your local computer.
OE is on the computer next to you; Yahoo is in a server somewhere out
there in cyberspace. Maybe you're confused about what Outlook Express
is - it's a program on your personal local computer that can retrieve
email from whatever email service you indicate. Yahoo is itself an
email service. You could set OE up to retrieve email from there, or you
can use their own web interface for that purpose. "Outlook Express" is
not itself an email service.
Maybe you had a web browser extension or add-on installed that
displayed email status for several email services. But I don't think it
was Yahoo, per se.