Death, what browser do you use?
Where exactly do you type it (adress bar, or little google search bar or any other bar)?
Do you have an autocomplete function turned on in your browser?
Maybe we don't have to alarm scott- please, describe your problem and actions more deatiled.
Having a signature is like keeping a gremlin.
Just don't overfeed it, don't make it wishy-washy and you'll be a good responsible Signature Keeper :]