GRANTs and %

[Kaan Oglakci]

Hi, 
For some reason when I try to set up grants for a database by typing this
GRANT ALL ON newstesting.* to clients@%  IDENTIFIED BY 'pass';

I get this error
ERROR 1064: You have an error in your SQL syntax near '%  IDENTIFIED BY
'pass'' a
t line 1

But when I type in a host name it works fine
GRANT ALL ON newstesting.* to clients@stripped IDENTIFIED BY 'pass'

I don;t really understand this host thing, can someone tell me what it
means?
At the moment can I only access the database?? 

Thanks,
Kaan.