I seem to have 90 points more reputation on SO than I have earned. This happened today at about 2:30pm GMT.
http://stackoverflow.com/reputation ** total rep 21278
But SO shows 21380. I was watching at the time and expected 21290, or there abouts.
The headline figure as displayed on your profile includes reputation gained or lost from deleted posts.
The figure displayed by the report is your true reputation taking these into account.
If you click on the "Trigger Reputation Recalc" button your headline value will be brought into line with the true value.
Reputation will now be kept in sync at all times. This change in behavior will roll out across the network soon, it's active here on meta currently.