From Homestar Runner Wiki
The vast majority of unreadable and unusable emails Strong Bad receives are "DELETED!!". While some are given to The Cheat for filing (or archiving) and others are made into origami by Strong Mad, Strong Bad takes great pleasure in purging his computer of most emails, doing so while screaming "DELETED!!". When he does this, the computer flashes the same word on the screen and emits a loud buzzing noise. When deleting emails, Strong Bad either types the word "deleted" out on the computer screen or presses a single key.
Strong Bad deletes any email that particularly annoys him, but some emails are especially susceptible. In particular, any time he receives emails including the question "How do you type with boxing gloves on?" or other such clichés, he promptly deletes them.
On at least one occasion (sisters), Strong Bad's control of his computer's delete function was nullified by the malfunctioning Tandy 400. This caused him to delete an email which he intended to respond to, and save an email which he intended to delete. A virus also once prevented him from deleting an email (virus). Ordinarily, however, his efforts to delete unwanted emails are infallible, whereas other characters (Homestar Runner and Coach Z) fail in their attempts, sometimes causing a computer error.
On the Tandy, the DELETED screen is a green background with black letters. (Oddly, "DELETED!" appears in the Compy's font.)
- Email homestar hair (almost, see fun fact below)
- Debut: Email spring cleaning
- Email sisters
- Theme Song Video (DVD version only)
- Email pop-up (as a pop-up in the pop-up book)
- Email retirement
On the Compy, the DELETED screen is a blue background with white letters.
- Email 50 emails
- Email huttah! (Most of the emails get DELETED in this episode)
- Email unused emails
- Email 2 emails
- Email car (almost, see fun fact below)
- Email replacement
- Email virus (A failed delete because of The Virus)
 Fun Facts and Abnormalities
- The very first deleted email (a Hairstyle Runner design) was in homestar hair. Strong Bad typed "delete that crap" instead of DELETED!!. The Tandy responded with "crap deleted".
- In the email spring cleaning, Strong Bad DELETES every email he receives.
- In the email sisters, the malfunctioning Tandy 400 causes Strong Bad to inadvertently delete the email he was trying to reply to. When he tries to delete the second email, it ends up being "saved forever". The save function is never seen again.
- In 50 emails, Strong Bad types "matt = DELETED!", and the email is in fact deleted with the word "MATT!" displayed on the screen. Homestar Runner also attempts (and spectacularly fails) to perform the "DELETED!" gag. He tries "BALEETED!", "DELTEATED!", "Del Taco?", and many other words. He ends up crashing the computer with a Flagrant Error.
- On the third email in huttah!, Strong Bad says "Moving on!" and the computer flashes "MOVING ON!!" when the email is deleted.
- In unused emails, Strong Bad winds up and screams "DELETED!", jumping in the air, spinning and landing a leg drop on the Compy and as a result of doing so, breaking his Clavicus. The screen then does the usual buzz about a second later.
- In labor day, when Strong Bad doesn't show up to the Labor Day party, Strong Sad jokes that Strong Bad's invitation may have been "da-leet-ed".
- In car, Strong Bad is about to delete the email, but Homestar saves the email from a "tired old Strong Bad joke" and is later "rewarded" with a punch in the face.
- In replacement, Coach Z's attempt at the word "DELETED" caused the Compy to flash "DELORTED!!" on a yellow screen, and the corresponding buzzer became distorted.
- In virus, Strong Bad tries twice to delete the offending email, but he is thwarted by the virus, receiving the messages "NICE TRY!" and "NOTTA CHANCE!!".
- The Lappy is apparently able to start emails over in a similar fashion to DELETED, as seen in do over. Both "DELETED!" and "Do Over!!!" use an animated explosion with accompanying sound effect when used on the Lappy.
- The pop up book in pop-up features DELETED!!, but makes the sound of Strong Bad's voice saying DELETED rather than the expected buzz sound. According to Strong Bad, it sounds more like "the lake head" or "Police Quest".
- In retirement, the Tandy requests one last email. Strong Bad obliges, deletes the email and, using Mountain Dew and denture tablets, blows up the Tandy in the process. In this appearance, the DELETED screen is in Old English font and is accompanied by organ music.
- The Lappy has an "Undelete" feature in Strong Bad's Cool Game for Attractive People. When Strong Bad uses it, the word "UNDELETED!" appears against a light blue background while the buzzer plays in reverse.
- In Dangeresque 3: The Criminal Projective, in the introduction for Extended Play, Strong Bad puts emphasis on "DELETED! Scenes" when listing the "DVD Bonus Stuff".
- In Fan Costumes '09, one of the pictures is of a "card-carrying Deletehead". Strong Bad responds with "Deleted!"