An ISP (Internet service provider) is an organization that provides services for accessing and using the Internet. Usually, for example, huge internet companies are tracked as ISPs because they create a lot of automated traffic and so it might be harder to recognize visits from their employees.
Basically, if your website visitor doesn't have their own IP address, they show up with the network name of their internet service provider (ISP).
Website visitor using WIFI in an airport or coffee shop.
Website visitor using their mobile network.
Website visitor on home Internet.
These visitors are not interesting from a Leadfeeder user point of view, since the target is to generate sales leads with Leadfeeder – that is, real companies visiting your website and showing interest in your services.
Leadfeeder is constantly increasing the number of blocked ISPs globally, but inevitably we haven't found a way to block everything yet. So when you see an ISP – or in fact any company you don't find interesting – you can just hide it and it won't count towards your lead quota anymore.
If you want to quickly do a search for ISPs in your Leadfeeder you can for example search by certain industries (you can see options in Leadfeeder).