CallingId installs a global hook?

I recently found out that this FF extension installs a global hook, why would it need one? Neither PG or snoopfree detected this type of hooking.
Any input is greatly appreciated.

 

CallingID is not a spyware nor an adware. It was tested by several independent sources and a list of clean awards for CallingID can be found at http://www.callingid.com/Press/CleanAwards.aspx

CallingID plug-ins provide a true safe browsing solution for the protection of individuals when using the Internet for e-commerce, online banking and accessing secure sites or any site where the user is required to provide private or personal data. Our solution uniquely provides an easy to use approach to assure users that they are accessing the site they intended. This is achieved by providing identification of the site ownership details and verification that the owner is a real organization conducting business at the address it claims to be.

If you have more specific questions, please let us know and we'll do our best to answer them

Yoram Nissenboim, CEO, CallingID

 

Thank you for your reply Yoram. Prior to installing Callingid I hade similar products: MacAffee siteadvisor, Wot and others on my computer, but none of these requested a windows global hook, and this is actually what lead me to question this add-on's behaviour.
It'll be great if you can shade some light on these two dll's request for a global hook:
C:\Program Files\CallingID\Firefox\Components\CIDDomFx.dll
C:\Program Files\CallingID\CallingIDIE.dll

Thanks again.