I'm a hobbyist who follows a number of web sites for my interests: Scale modelling, motor racing, military, naval and aviation history. None of these involve purchases or financial information, and often I'm not registered as a member on these sites. With some sites that I've visited in the past, and bookmarked, I'm now receiving this warning message from Bitdefender: "Your connection to this web page is not safe due to an unmatching security certificate. This means that the certificate was issued for a different web address than the one it is being used for, and you run the risk of exposing your data by accessing this page."
What personal data of mine actually can be exposed or compromised by continuing and visiting such sites?