First off, Ratebeer:
Slightly malty, no hop flavor or aroma. Medium to dark brown in color with very little head or carbonation. Mild refers to lack of any hop flavor or aroma. Serve with traditional pub fare.
Color ranges from reddish-brown to dark brown. Lower in alcohol than porter, medium to full body flavor. Appropriate foods are apple pie, pork with brown sauce, beef vegetable soup and cheddar.
This is what BeerAdvocate has to say:
Dark Mild Ale
The quintessential British session beer, like its name suggests, a Mild is known for its low level of hops character. Alcohol content is traditionally very low. Grainy to toasty malts might be present, but expect some body from the high dextrins produced in brewing. Low carbonation with a near still, bubbly head. Colors can range from gold to dark brown. Traditionally a draft beer made popular in London and the Midlands of England.
English Brown Ale
Spawned from the Mild Ale, Brown Ales tend to be maltier and sweeter on the palate, with a fuller body. Color can range from reddish brown to dark brown. Some versions will lean towards fruity esters, while others tend to be drier with nutty characters. All seem to have a low hop aroma and bitterness.
And finally, the most pretigious of all, the BJCP:
Dark Mild Ale
Overall Impression: A light-flavored, malt-accented beer that is readily suited to drinking in quantity. Refreshing, yet flavorful. Some versions may seem like lower gravity brown porters.
History: May have evolved as one of the elements of early porters. In modern terms, the name “mild” refers to the relative lack of hop bitterness (i.e., less hoppy than a pale ale, and not so strong). Originally, the “mildness” may have referred to the fact that this beer was young and did not yet have the moderate sourness that aged batches had. Somewhat rare in England, good versions may still be found in the Midlands around Birmingham.
Southern English Brown Ale
History: English brown ales are generally split into sub-styles along geographic lines. Southern English (or “London-style”) brown ales are darker, sweeter, and lower gravity than their Northern cousins. Developed as a bottled product in the early 20th century out of a reaction against vinous vatted porter and often unpalatable mild. Well suited to London’s water supply.
Ingredients: English pale ale malt as a base with a healthy proportion of darker caramel malts and often some roasted (black) malt and wheat malt. Moderate to high carbonate water would appropriately balance the dark malt acidity. English hop varieties are most authentic, though with low flavor and bitterness almost any type could be used.
Do you think these descriptions match what we're seeing in the recipes? I'd appreciate your comments.
I will say one thing. BeerAdvocate says of Dark Mild: "Alcohol content is traditionally very low". I like that one. Like "IPA is strong". When exactly does the "Traditional" period cover? For Dark Mild, it's post WW II. For IPA, it seems to be 1830.