I've just looked at the site and found some pages in English 😃
From what I can see, they are offering to provide a service that gives you the company name and fax/phone of people visiting your website. Many fairly basic web traffic analysis tools can give you hostname and location, which if you link to an online global business directory can give you the phone and fax numbers for the office of that company nearest that location.
However, be aware that this information is far from perfect. It falls down with dial up, although not many medium to large enterprises use dial up these days, the major problem is people who outsource their mail to a 3rd party hosting company, or have central internet access via VPN or something.
For example, if someone from Ericsson UK visits my site, and because of the way they handle internet access it shows up as Ericsson in Kista, the phone and fax number isn't a lot of good. Mind you, even if you have the UK phone number, it really isn't a lot of use in trying to find who, from which dept was on your site from a company of that size.
Sorry to not be more helpful.
Blu