"Linen" postcards were produced from the late 1930's through the early 1950's. They were produced on paper with a high rag content which gave the postcard a fabric type look and feel. They can be identified by a sort of crosshatch pattern on the face of the card. Some cards show a more prominent pattern than others due to a greater or lesser rag content. At the time this was a less expensive process than printing of the white border postcards of the 1930's.  Along with advances in printing technique, linen type cards allowed for very vibrant ink colors.

They were immensely popular and consisted primarily of scenic views, city/town views, national monuments, and comic type cards. Roadside establishments at the time frequently used postcards as a form of cheap advertising. 

Curt Teich was the most prominent and probably largest publisher of linen type postcards. Other large publishers include Asheville Postcard Company, Tichnor, and the Stanley Piltz Company

The printing of linen type postcards began to give way in the 1940's to Kodachrome / Ektachrome glossy type prints. Although some publishers, particularly in the south, continued making linen type cards into the early 1950's. Linen postcards remain highly popular among collectors. As with any type postcard, the subject and condition of the cards are the determining factor in value. Among the more highly collectible subjects are "main street" type scenes, scenes along Route 66, military propaganda, and Black Americana. However, even the most common linen postcards can make a very desirable addition to a postcard collection.

The photo is an example of a linen postcard.