Since Vodka tends to be a neutral spirit, it lends itself to blending with flavors and fortifying other beverages. In the 19th century, high-proof "Russian spirit" was held in high esteem by Sherry producers in Spain, who imported it to fortify their wines.
Neutral spirits are still used to fortify Port, Sherry, and other types of fortified wines, although the source of alcohol for such purposes these days tends to be the vast "wine lake" that has been created by European Union agricultural practices.
Flavored Vodkas have been produced from the start, originally to mask the flavor of the first primitive Vodkas, but later as a mark of the distiller's skill. The Russians and Poles in particular still market dozens of flavors.