Hi Michelle, see this post from Sumi: #112 Click on the "Report" button at the bottom left of your post so a moderator will see it and change your guess.
It's the number of "messages". For example, right now the number of messages is
18,931,508
@Hopperkiller see this post from one of our moderators, Sumi:#115
Just click on the Report link (bottom left of your post) and the change will be made.
Looks like it's ok to change a guess as long as it follows what the rules on page 1 say:
"You can change your guess to a different day/hour IF IT IS NOT TAKEN but if you choose another day you allow someone else to take your previous guess.
You can change your guess as many times as you want...