need help on the signature thing

can anyone help me please.....i am trying to update my signature and it keeps not working saying:

Your signature cannot be longer than 500 characters including BB code markup.

What does that mean? And I have looked at other signatures and mine isnt really long or wide in comparison.....what am I doing wrong???

Your signature space gets bigger once you reach 50 posts

Youve reached the maximum for someone with your level of posting

delete - sorry

ahh...thanks starlight....that makes more sense now.....it was totally doing my head in, couldnt figure out why it wouldnt accept it!!..xx