Windows Mobile contact data
Despite their long-time dominance of desktop systems, Microsoft never managed to achieve a large share in the mobile device market. They got all sorts of sponsorship deals that resulted in, for instance, the NFL making a big deal about the tablets being used on their sidelines being Microsoft models... don't you dare call 'em "iPads"! And various movies and sitcoms had people conspicuously using Microsoft devices and "Bing-ing" rather than "Googling". But even making deals with one-time mobile device leader Nokia to put Microsoft systems in their new models didn't give them the dominance of this field they wanted. People kept on using Apple and Android devices instead.
Anyway, like other brands of devices Microsoft's Windows Mobile devices stored contact information on people the device's user wished to call, text, or email, and provided some means of importing, exporting, transferring, and backing up this data.