When updating the website, the engine has to retest 
all links to see if they have been updated - or not. 
This is done through an update request.

Some websites, however, always respond to these 
request as it the content had been modified. Often, 
these websites are dynamically-generated pages 
(asp,cgi,php..) and they just can not handle update 
process.

You can, with the current (RC-8) version, activate 
the "Update hack" option tat will consider a file 
updated if its size is the same.

This should work for almost all sites, except those 
who have dynamic pages AND doesn't give any Content-
length header!