This error is a security error designed to protect you against fraudulent websites/warn you against fake security certificates.
Just in case you're not aware, when you connect to a website through SSL (
HTTPS://), it requires a certificate. There are two options, the site can purchase a certificate from a legitimate, trusted certificate provider, which will prevent this kind of error from happening. Or, they can generate they're own, self-signed certificate, which will generate an error. In addition to that, some people don't understand certificates and add wrong ones to the wrong sites, which will also generate the above error.
So what this is telling is the Yahoo certificate used for rogers.yahoo.com is expired and they need to renew it with a Trusted Provider or assign the proper certificate to the listed subdomain.
As long as the url isn't being hijacked and you're not being redirected somewhere else, then most likely they just forgot to update their certs. If you're not doing any financial transactions or have any secure information that you use on that site, then you can, if you want, go ahead and just accept the broken certificate and continue viewing the site.