Why do some sites display the wrong font that should be?

Question

Browsers

In general, this font, the one in the picture, is displayed on some sites, such as ebay, tumblr, Google services, and many other places. In Internet Explorer, the same thing, on a neighboring computer as well. Tell me how to cure? Windows 8.1
Ebay:

Answer 1

By the way, I guess what's going on with you, judging by the picture. Most likely the problem is in the standard fonts installed on your computer. It is worth trying to reinstall the default fonts.