Pam has it right and so does Don and the others. Here's a short list I made up over the years.

Postcard Archaeology Helper

Arcade Cards - postcard size, but plain back.
Chrome - Any card after 1939 with a shiny paper surface.
Deckle-edge - ripple or serrated edge cards
Linen - Postcards from 20s thru 50s using textured cross hatched surface.
Real Photo - Actual photo on photographic paper, not a printed image of a photograph.
View Cards - Cards that feature cities and places within cities.

The Amt. of postage can help date the card.
1872 (1 cent), 1975 (7 cents),
1917 (2 cents), 1976 (9 cents),
1919 (1 cent), 1978 (10 cents),
1925 (2 cents), 1981 (12 cents),
1928 (1 cent), 1981 (13 cents),
1952 (2 cents), 1985 (14 cents),
1959 (3 cents), 1988 (15 cents),
1963 (4 cents), 1991 (19 cents),
1968 (5 cents), 1995 (20 cents).
1973 (8 cents),

USPS Zipcode instituted in 1962
Extended Zip for automation added 198?

Phone Numbers: (I haven't specified this because it varies by city and state)
Were four or five numbers until ????
Dropped Exhange Names in ????
Introduced direct-dial Area Code + seven numbers ????

On the Curt Teich (or C.T. Art-Colortone) there's an alpha-numeric date code.
The "alpha" part indicates the decade
A=1930's
B=1940's
C=1950's
D-1960's
The numeric part indicates the year....so 7A would be 1937, 5C would be 1955, etc.
The date code is followed by another number, possibly the scene.