"View this Thread" from email

Once I get an email about a thread I'm subscribed to, theres a tab at the bottom>
"View this Thread".. SOMETIMES when I click it, I HAVE TO log in to view it..
OTHER TIMES it goes straight to the entire thread..
Another question>>
When I click on a "view this thread" link, SOMETIMES it will go to the "first un-read" post..
OTHER TIMES it will go to the #1 POST.. Whats-up with that???

"View this Thread" from email