Rum is distilled from fermented juice of sugar cane, sugar cane molasses or other sugar cane based products or by-products. According to US requirements, it must be distilled at less than 95% abv (190 proof), and bottled at 40% abv (80 proof) or higher. Rum is a spirit that embodies a very wide degree of variations. It can be clear and almost devoid of significant character besides the slight sweetness that hints at its sugary origins, or it can be deep, dark, and rich, befitting the thick molasses from which it may have come, even though it would have come out of the still crystal clear. Few spirits have the diversity of flavor that you can find in rum, which can make it difficult to determine which rum to use in a cocktail which simply says "rum", even when they do mention "dark rum", "Jaimaican rum", or "aged rum" the potential options are still pretty broad. 

The following recipes on this site use rum:

Añejo Highball
rum, orange curaçao, lime juice, Angostura Bitters, ginger beer,
Apricot Lady
rum, apricot brandy, lemon juice, orange curaçao, egg white,
Bacardi Cocktail
rum, lime juice, grenadine,
Beachbum's Own
lemon juice, pineapple juice, orange juice, passion fruit syrup, Licor 43, rum, rum,
Bermuda Rum Swizzle
rum, lime juice, pineapple juice, orange juice, falernum,
Between The Sheets
brandy, rum, Cointreau, lemon juice,
rum, maraschino liqueur, orange curaçao, grenadine,
Captain's Blood
rum, lime juice, simple syrup, Angostura Bitters,
Cuba Libre
rum, cola, lime wedge,
rum, lime juice, simple syrup,
Dark N' Stormy
rum, ginger beer,
Egg Nog
eggs, sugar, salt, rum, heavy cream, milk,
El Presidente
rum, dry vermouth, red curaçao,
Eye Opener
rum, orange curaçao, apricot brandy, grenadine, egg yolk,
rum, lime juice, sweet vermouth, crème de cacao, grenadine,
Fog Cutter
lemon juice, orgeat, rum, brandy, gin, sherry,
Good Hurt
rum, grapefruit juice, Dubonnet, simple syrup,
Hot Buttered Rum
butter, brown sugar, water, rum,
Jolly Roger
rum, rum, orange juice, falernum, Angostura Bitters,
Mai Tai
rum, rum, lime juice, orange curaçao, orgeat,
rum, lime juice, simple syrup, mint, soda water,
Old Cuban
lime juice, simple syrup, rum, Angostura Bitters, mint, champagne,
rum, Cointreau, lemon juice,
Planters Punch
rum, lemon juice, orange juice,
rum, dry vermouth, Cointreau, lemon juice, grenadine,
Pusser's Painkiller
rum, pineapple juice, orange juice, coconut cream,
Queen’s Park Swizzle
rum, simple syrup, lime juice, Angostura Bitters, mint,
Strega Daiquiri
rum, Strega, lemon juice, orange juice, orgeat,
rye whiskey, rum, port, Angostura Bitters, orange bitters,
rum, sweet vermouth, dry vermouth, Benedictine, orange juice,
Tom and Jerry (batter mix)
eggs, rum, cinnamon, cloves, allspice, cream of tartar, sugar,
rum, Benedictine, falernum, lime juice, Angostura Bitters,
rum, Cointreau, lemon juice,
lemon juice, lime juice, pineapple juice, brown sugar, passion fruit syrup, rum, rum, rum, Angostura Bitters,