1. Secret VFD Websites: Season 1
Each trailer released for Season 1 included a hidden VFD phrase, either spoken or written on a prop. These VFD phrases, if input as a URL, led to promotional secret websites containing Season 1 concept art, stills, and GIFs.
The secret websites are no longer active; they now redirect to the Series of Unfortunate Events page on Netflix. Archive links and screenshots are included below.
Very Flammable Dandelions
The first Teaser Trailer, released October 4, 2016, included a wooden crate prop printed with the label "VERY FLAMMABLE DANDELIONS". Located at the secret website VeryFlammableDandelions.com was concept artwork of Count Olaf's house from The Bad Beginning episodes.
Visceral Fantabulous Debut
The second teaser trailer "Meet Count Olaf", released November 3, 2016, included a clip of the Daily Punctilio headline "VISCERAL FANTABULOUS DEBUT!". Located at the secret website VisceralFantabulousDebut.com was concept artwork of Uncle Monty's reptile room from The Reptile Room episodes.
Vital Fan Disclosure
The social media announcement of the first full trailer, released November 17, 2016, described the trailer as a "vital fan disclosure". Located at the secret website VitalFanDisclosure.com was concept artwork of Aunt Josephine's house from The Wide Window episodes.
Valorous Farms Dairy
A video of "Holiday Tidings from Count Olaf" was posted on the show's official social media accounts on December 22, 2016. In the background of the video was a barn labeled "VALOROUS FARMS DAIRY" (from the Unauthorized Autobiography). Located at the secret website ValorousFarmsDairy.com were a selection of "Grim Greetings" holiday cards.
Unhappy Holidays from A Series of Unfortunate Events
If you seek holiday cheer to share with your loved ones, look elsewhere.
Various Frequent Disasters
A later trailer titled "The Facts", released January 9, 2017, included the spoken phrase "Various Frequent Disasters" in Lemony Snicket's narration. Located at the secret website VariousFrequentDisasters.com were a selection of "Reaction GIFs from the Dreadful Count Olaf".
Very False Documents
The social media announcement that Season 1 was now streaming (January 13, 2017) warned viewers:
"We regret to inform you that #ASOUE is now streaming. Soon, the very false documents in our credits will be the least of your worries."
Located at the secret website VeryFalseDocuments.com were cheerful GIFs of cute animals, with the tagline: "Welcome to a world of laughter, comfort, and happy endings." A button labeled "I wish to delve into a world of tragedy and disappointment" triggered a confirmation pop-up window, then led to the Series of Unfortunate Events page on Netflix.
Other
Forty other VFD website domains were registered by the same IP address at Netflix, but were not used for promotions. The unused websites contained a themed 404 message.
2. Count Olaf on Acting
Netflix interviewed Count Olaf about his acting talent for two videos to promote Season 1:
And The Winner Is... (2017 Golden Globes)
An Unfortunate Actor on Acting
3. Netflix Kitchen: Baudelaire's Flaming Mansion
Netflix Kitchen constructed a replica of the Baudelaire mansion out of chocolate, then set it on fire.
1. Secret VFD Websites: Season 2
The first two teasers released for Season 2 included hidden VFD phrases. These VFD phrases, if input as URLs, led to promotional secret websites. The secret websites are no longer active; they now redirect to the Series of Unfortunate Events page on Netflix. Archive links and screenshots are included below.
Vastly Frightening Decision
The show's renewal for a second season was announced March 13, 2017 via a teaser video posted on the official social media accounts. The text shown in the video and the narration by Patrick Warburton led to the secret website VastlyFrighteningDecision.com, which contained a letter announcing the renewal and four GIFs of scenes from the first season.
Teaser video
Verse Fluctuation Declaration
On January 1, 2018, the official social media accounts posted a clip of the song "That's Not How the Story Goes" with the caption:
There's no happy endings,
not here and not now,
this Verse is all Fluctuation and woes,
you might dream that justice and peace win the day,
but that's not how the Declaration goes (.com)
This led to the secret website VerseFluctuationDeclaration.com, which contained a coded poem:
A new year has arrived to traverse
Note that you likely may feel very terse
Awaiting the year
You are quite right if you fear
Below the surface it only gets worse.
Below the poem was a link to Netflix's website with a New Year's Day Message from Count Olaf. The message video was also posted on YouTube the following day.
Video: A Message from Count Olaf
2. Research Wall Grid
The official Instagram account @unfortunate posted excerpts from Lemony Snicket's research wall about the Baudelaire case. From December 27, 2017 to February 23, 2018, the excerpts were carefully arranged into a grid of Instagram posts so that the whole wall could be viewed. On March 5, 2018, the account posted a Daily Punctilio headline AESTHETICALLY PLEASING GRIDS ARE OUT with the caption "Instagram Schisms: IN". This new post shifted the research wall grid out of alignment (the "schism") and revealed a VFD eye hidden in the stains and string on the research wall.
3. Mulctuary Money Management Filing Cabinet
In March 2018, the official Instagram account @unfortunate and its supplemental account @mulctuary.money.management posted documents from Mr. Poe's filing cabinet of potential guardians for the Baudelaires. Volunteers were asked to help select the most appropriate guardian. Clicking on each file cabinet drawer revealed a network of supplemental Instagram accounts: @choose.aunt.josephine, @choose.count.olaf, @choose.lucky.smells, @choose.prufrock.prep, @choose.the.squalors, and @choose.uncle.monty.
After choosing a guardian and opening that file cabinet drawer (i.e., visiting the supplemental account), volunteers could search through the guardian's home (represented by a grid of Instagram posts). Swiping to the additional photos within each post revealed details of that scene in the guardian's home. For example, swiping on the post of Aunt Josephine's desk revealed a photo of the desk contents, as if you were searching her desk.
During the search of each guardian's home, volunteers could find hidden scraps of paper, which when assembled read "I didn't realize this was a sad occasion".
4. Message from Count Olaf
In addition to his New Year's Day message (above), Count Olaf also had special messages for Saint Patrick's Day and the Bachelor finale.
5. Tiny Kitchen: Pasta Puttanesca
Netflix sponsored the "Tiny Kitchen" to prepare Pasta Puttanesca.
1. Secret VFD Websites: Season 3
Verified Fealty Detector
As part of the Season 3 marketing, the show's official social media accounts posted a video of Count Olaf drinking tea (December 20, 2018). Hidden inside the sugar bowl was a card from the Hotel Denouement with a URL written on it for the secret website VerifiedFealtyDetector.com. This website contained an "unfortunate quiz" to determine whether you were a fire starter or fire fighter. After completing the quiz, participants could view a Sneak Peek clip from the Slippery Slope Part 1 episode, in which Fernald helps Sunny break ice to catch salmon.
Other
Other social media posts during the Season 3 marketing included additional VFD phrases, but as far as I know these were red herrings and never led to a secret website.
Verbal Fridge Dialogue (December 5, 2018)
Very Final Definition (December 6, 2018)
Variably Fine Drama (December 19, 2018)
Very First Day (December 30, 2018)
Very Frustrating Delivery (December 31, 2018)
Video: Olaf reveals the sugar bowl contents
Video: Sneak Peek
An Unfortunate Quiz walk-through
2. The Awful Advent Calendar
In December 2018, the official Instagram account @unfortunate revealed photo stills and clips from the upcoming Season 3 in the form of an advent calendar. Not every day was included; advent calendar posts were made only for Days 1, 4, 6, 8, 13, and 15.
Day 1
Day 4
Day 6
Day 8
Day 13
Day 15
3. Loney M. Setnik's A Series of Fortunate Events
On January 4, 2019, three days after the Season 3 premiere, the official social media accounts posted a parody trailer for "Loney M. Setnik's A Series of Fortunate Events", named after the fake author of The Pony Party!
Video: Loney M. Setnik's A Series of Fortunate Events
4. A Series of Malevolent Recordings
On January 8, 2019, one week after the Season 3 premiere, the official social media accounts posted several parody ASMR videos featuring Patrick Warburton.
Video 1
Videos 2 through 10 (merged)