I couldn't find anywhere else we're tracking which sites we'll break when we disable SSLv3 in Firefox 34. Tech Evangelism seems as good a place as any dbaron reported that https://tmobile.ecustomersupport.com/ requires sslv3 to connect. That site is used to refill minutes on a pre-paid SIM. SSLLabs considers it "poodle mitigated" because the site uses RC4 with md5. https://www.ssllabs.com/ssltest/analyze.html?d=tmobile.ecustomersupport.com
Be on Safari, Opera (Blink), Firefox I get a blank page. Is this site really used? On which browser is it working?