my youtube n yahoo mail worked before KATE/caterpillar froze my touch screen. I had to use Ziphone to jailbreak it and start from scratch ( i didnt let my "backup" on itunes get "restored" back into my iphone)
anyhow, now that i have my fresh phone. Youtube n yahoo doesnt work. It says Yahoo acct verification failed. THe IMAP server "imap.apple.mail.yahoo.com" is not responding. Check your network connection and that you entered the correct information in the "incoming mail server" field...
err.. i didnt have to manually ENTER any information in the incoming mail server section.