Many Opera users using the SBC services have encountered this problem: for no reason I'm aware of, the webmaster of SBC's sites such as sbcglobal.net and dsl.sbc.yahoo.com has decided not to let Opera-users access their pages.
To get around this, we can use the free tool Proxomitron to disable SBC's Opera detection. For information about downloading, installing and using Proxomitron, see the proxomitron.info site or the Proxomitron's page in the Opera 7 wiki.
The code that detects Opera and redirects you to the upgrade page reads (excerpts):
this.op=(window.opera ? 1:0);
.
.
var oBw = new yg_Browser();
if (oBw.ns||oBw.op||(!oBw.fb&&oBw.ns6&&oBw.agt.match(/6.[01]/))) {
document.location.href = "http://sbc.yahoo.com/browser_upgrade.html";
}
The simplest fix is to just disable the forward. You can download a Proxomitron configuration file that will do so. I don't know if Opera-detection is (ab)used in other parts of the site, if so you may want to create a different filter.
To use the file, save it on your hard disk and in Proxomitron, then choose . The file contains three different filters, only one of them enabled by default. If the active filter does not prevent the detection, try one of the others. Note that they are experimental as I am not an SBC customer myself.
To learn more about browser blocking and what you can do, visit Opera's Open The Web project.