I was unaware of this flip side of blacklist, although it appears that it is not all that uncommon nor all that new. I’ll first look at blacklist. It has an interesting history and, as a bonus, white list can be defined as its opposite.<2014 “Vodka and other pure spirits have long been white-listed for suffers of celiac disease, even in the absence of labels. The Academy of Nutrition and Dietetics has advised that distilled spirits are gluten-free unless a flavoring or other additive has been added to the liquor.”—Scientific American, February, page 25>
BLACKLIST / BLACK LIST noun : A list of persons or organizations that have incurred disapproval, displeasure, or suspicion and are therefore to be boycotted or otherwise penalized; list of people or things that are deemed unsafe or undesirable.
BLACKLIST / BLACK LIST transitive verb : To place on a blacklist; blackball, boycott, ostracize, bar, ban, shun, shut out.
Etymology: The blacklist is centuries old, having originated with a list England’s Charles II made of 58 judges and court officers who sentenced his father, Charles I, to death in 1649. When Charles II was restored to the thrown in 1660, 13 of these regicides were executed and 25 were sentenced to life imprisonment, while the others escaped. [[This is according to The Facts on File Encyclopedia of Word & Phrase Origins. However, the OED offers two quotes, 1624 & 1639 that predate the death of Charles I. Evidently, the Charles II list of 58 served to popularize the expression, but was not its origin.]]
WHITE LIST / WHITELIST/ WHITE-LIST noun:
1)  A list of people or organizations considered worthy of approval or acceptance; a list of things deemed safe, acceptable, or desirable. [modeled after, and the opposite of, ‘blacklist.’].
2) [circa 2000] (Internet): a) A list of e-mail addresses, IP addresses, websites, or programs that are deemed spam-free / virus free. b) A list of e-mail addresses or IP addresses a user wishes to receive e-mails from that overrides any blacklists and spam filters that would otherwise have prevented delivery.
WHITE LIST / WHITELIST / WHITE-LIST transitive verb:
1)  To place on a white list.
2)  Internet: Specifically, to place on an Internet white list.
(Oxford English Dictionary, American Heritage Dictionary, Brewer’s Dictionary of Modern Phrase & Fable, The Facts on File Encyclopedia of Word and Phrase Origins, WordSpy.com and Webopedia.com)
The following quotes are from the Oxford English Dictionary and archived sources:
_________________________<1860 (from the Daily Southern Confederacy, Atlanta, Georgia) “From the best and most reliable information, we present to the Southern people the names of wholesale mercantile firms of New-York, which are friends and enemies to our institutions. . . . Our Black and White List will be added to from time to time until the catalogue is exhausted. We have true Southern-born men in New-York who will keep us posted as to the status of each firm or concern which are attempting to do business with the South.”—New York Times, 22 February> [[this predates the OED’s earliest quote by 40 years and refutes the claim of Brewer’s Dictionary of Modern Phrase & Fable that “The term dates from the beginning of the 20th century.”]]
<1890 “The ‘White List’ Association: . . . To be ‘white-listed’ indicates to a manufacturer, merchant, or dealer in any wares, and to the public also that an investigating committee of intelligent women have agreed that he pay women in his employ decent living wages, and that such being the case other women will patronize him.”—Washington Post (D.C.), 18 January, page 4>
<1900 “The Labor Leader's ‘white list’ is the final stroke—the white flag held up to Liberalism at the moment when we are on the verge of victory over it.”—Collected Letters (1972) of George Bernard Shaw, edited by Dan. H. Laurence, 31August, II. Page 182>
<1939 (advertisement) “Furs.—Avoid those tortured to death. Buy only those named on the Fur Crusade White List.”—Country Life (London), 11 February, page xxi/1>
<1977 “One idea is a ‘white list’ of preferred drugs or a list of excluded drugs for which the N.H.S. would not expect to pay.”—Lancet (London), 30 April, page 963/1> [[N.H.S. = Britain’s National Health Service]]
<1985 “A blacklist of drugs not prescribable in the NHS will be written into the NHS regulations . . in addition, a whitelist will be issued saying what drugs may be prescribed.”— British Medical Journal (Clinical Research Edition), Vol. 290, No. 6465, February, page 406>
<1998 “The controversial proposal would mean Britain abiding by asylum legislation agreed in Brussels, including an EU-wide definition of a refugee, the treatment of asylum seekers and the ‘white list’of countries where no serious risk of persecution is considered to exist.”—The Independent, 6 December>
<2001 “The application permits the ‘white listing’of known non-malicious programs, which are allowed to run while all other code is still monitored.”—Information Security, February>
<2003 “So how do we start fixing [spam]? Clearly, technical approaches are part of the solution. Apple and Microsoft have pretty good but far from flawless filters in their mail clients. Measures taken before the junk gets to the in box include ‘blacklisting,’ which blocks stuff from known spammers, and ‘whitelisting,’ which permits only e-mail from preapproved senders.”—Newsweek, 24 February>
<2006 “We're told the IT folks said a non-political computer program was to blame for what the netminders called ‘blacklisting.’ The site was promptly unblocked, or ‘whitelisted.’”—Washington Post (D.C.), 17 July>
<2010 “The bank also had supplied documentation in a bid to get on the OECD's so-called ‘white list’ of banks that cooperate with international norms on money-laundering and terrorism, . . .”—AP Worldstream, 22 September> [[OECD = Organisation for Economic Co-operation and Development]]
<2013 “The government is drawing up a list of sites inadvertently blocked by the filters it asked internet service providers (ISPs) to implement. . . . The whitelist will be used to ensure the sites are not immediately blocked.”—BBC, 30 January>
Ken G – February 11, 2014