FYI... I noticed on my iPhone that the symbol that shows an unread thread is no longer working. Instead of a small crimson circle - it is now just a white box or square outlined in black. The challenge is every thread - no matter if you have read them or not are using the white box (black line). So now you cannot tell if you have read the thread or not.
It's strange because this issue just popped up this week when reading the mobile site on my iPhone... I've never had this issue before.