I used to get that over 500 thingy too.
What you have to do is go into your control panel/signature and comments.
Than put your cursor at the beginning right before "My Site" and hold down the delete key till it's all gone.
Then start fresh.
Each time you alter your sig there are bits and pieces of your old sig still hiding in the background.
Like the font commands, color, bold, italics, underline, size.
For me I tried listing my old Mackie Onyx 1640 but the comma was over the edge.
I counted and came up with 42 characters??????
One day I heard a little snapping sound sort of like a pencil breaking and wiped the whole thing clean and gave up.
When I calmed down a little, I PM'd someone at Cake and was told about the hidden remnants.
Since I deleted from the beginning, all remnants deleted too.
Presto a full 500 - 550, whatever it is was available once again.
So it's a good idea that if and when you change up sig's to wipe it all out and start fresh.
Don't just delete a line or two and add new info.
As I was typing this long winded off topic thread it occured to me that all you sig items are links.
As you know, links can be rather lengthy not to mention the hidden code Cake adds when you use the insert link command.
Strong possibility that you have exceeded the limit.
Try maybe cutting it down to My Site, My Services and My Truth.
Just a suggestion.
As an un-offendable Jersey-ite you can tell me to blow it out my clam-hole too.
Mike