Platform: Dreamcast

In August 1999, one month before the Sega Dreamcast's North American launch, Sega partnered with AT&T to make AT&T WorldNet the preferred internet service provider for the Dreamcast's online services. The Dreamcast's access to WorldNet launched as part of the US-based ISP SegaNet in September 2000. However, SegaNet would shut down its dial-up internet access less than a year later on July 20, 2001, and all online support for the console would be discontinued two years later in 2003. For the Dreamcast versions of Daytona USA and Alien Front Online, they used IP addresses grouped together in a network block owned by AT&T that were hardcoded into the games' servers, so when the partnership ended and SegaNet's dial-up service was shut down, the online services for those games were inadvertently taken down early as well. Years later, fans would unofficially restore the game's online features through private servers.

Bleem! was a PlayStation emulator released for Microsoft Windows 98 and the Sega Dreamcast. Unlike the vast majority of emulators before and since, it was released as a paid product on store shelves. Bleem!, although very impressive for the time and capable of running on low-end PCs, had many compatability issues, with the only game that ran perfectly on Windows Bleem! being the US version of One, while the only games that could be run at all on Dreamcast were Tekken 3, Metal Gear Solid, and Gran Turismo 2, all with specialised emulators released on their own "Bleemcast" discs.

Sony would sue Bleem! twice over alleged copyright infringement, and despite all odds, Sony lost due to Bleem!'s use of screenshots in promo material and the PS1 BIOS being protected by fair use. However, a mix of legal fees and Sony threatening retailers stocking Bleem! products with subpoenas would force Bleem! off of shelves anyway, and its website would be replaced with an image of Sonic The Hedgehog mourning at a grave with the Bleem! logo carved on it. Bleem! would countersue Sony for anti-competitive activity.

The popularity of Bleem! would lead both Sega and Microsoft to attempt to work with Bleem! officially to make PS1 games run on Dreamcast and Xbox, though these plans fell through due to Sega being afraid of Sony's litigation, while the developers of Bleem! simply felt Microsoft wasn't paying high enough for the license for Bleem! (something they had come to regret in the years since).

Despite Floigan Bros. being initially developed prior to the Dreamcast's release in 1999 (of which the main characters Moigle and Hoigle made cameos in the Dreamcast advertising campaign "It's Thinking"), and then-President of SEGA's American division Bernie Stolar saying that "Floigan will do for SEGA what Mario did for Nintendo", the game would go through developmental setbacks until finally releasing on July 30, 2001, months after SEGA ceased production on SEGA Dreamcast.

Because of this late release window, several pieces of monthly on-disc DLC for the game, as well as the concept of exchanging Moigles through the Dreamcast VMU, were left on the cutting room floor.

In the 1999 Sega Dreamcast commercial for Crazy Taxi, the DMV features the address number 666 (the Number of the beast) in reference to common complaints about long wait times and poor service at DMVs.

As part of their plan to launch the Dreamcast in Europe, SEGA created an official sponsorship with Arsenal FC (a British soccer club). The team wore Dreamcast branded shirts when they played in their home stadium, and SEGA branded shirts when they played away from home. Because of this, the club was mocked when they played against an Italian team, as 'sega' is an Italian derogatory slang term for masturbation.

In 2001, Sega teamed up with Pace to create a Dreamcast/cable box hybrid. The box was apparently meant to switch between live TV and downloaded games (including demos). It would also have had an internal 40GB HDD to store data.

While playing a Dreamcast disc on a device that reads CD files usually produces a warning message, Seaman, Shenmue, and Skies of Arcadia each have unique warning messages on each disc, all provided by the game's voice cast. On Seaman's disc, the voice actor for the Seamen will jokingly warn the player that attempting to play track one will infect their household appliances with viral diseases, and the Skies of Arcadia cast informs the player that they can't save the world while stuck in a CD player. All three Shenmue messages feature different characters from the game warning the player that attempting to play track one (which contains game data) would produce harmful results.

While the console had an official adapter to allow for the video signal to be channel through a VGA cable, some games don't support the feature. It was later made possible to bypass this restriction through the use of a Code Breaker cheat disc.

If there is a Puyo Puyo Fever save file on a VMU attached to the console, it's possible to press START on the system menu to toggle an alternative 3D menu that can have its viewpoint moved.

Inserting a Dreamcast disc into a CD player or a device that reads CD files, a warning message will play, stating "This is a Dreamcast disc and is only for use on a Dreamcast unit. Playing this disc on a hi-fi or other audio equipment can cause serious damage to its speakers. Please stop this disc now."

Some Dreamcast games supported the Jump Pack, a haptic feedback device similar to Nintendo's rumble packs. It was sold separately and could be plugged into the controller. In Japan, the Jump Pack was named the "Puru Puru Pack", and in Europe, it was named the "Vibration Pack".

A Dreamcast light gun was never released in the USA until Mad Catz developed the Dream Blaster, which was reminiscent of the type 2 phaser found in Star trek. Sega did produce their own official light gun, but it wasn't sold in the United States, possibly because Sega didn't want its name on a gun in light of recent school shootings (the Columbine High School massacre).

There was a camera for the Dreamcast called the Dreameye. It could only store 31 pictures in jpeg format, and was only released in Japan.

Visual Memory Units (VMU) each held 128KB. The combined capacity of all VMUs ever sold is approximately 1TB, enough to store all 730 games ever released for the Dreamcast.

In 2001, Sega's president Isao Okawa privately donated all $695.7 million of his own company stock to save Sega from going bankrupt due to the failure of the Dreamcast. He died shortly afterwards from heart failure at the age of 74.

The Dreamcast startup sound was composed by Japanese electronic/classical musician and former Yellow Magic Orchestra member Ryuichi Sakamoto. Sakamoto, by then internationally renowned for his film scores, was a personal friend of Kenji Eno, who came up with the console's name.

Ironically, SEGA's GD-Rom technology was created as DVDs were not available for SEGA, and they wanted to create a disc that would be hard for pirates to copy and use.

"Sega intended to use the format to curb piracy common to standard compact discs and to offer increased storage capacity. It is similar to the standard CD-ROM except that the pits on the disc are packed more closely together, resulting in a higher storage capacity: around 1.2 gigabytes, which is almost double the storage capacity of a typical CD"

The Dreamcast is infamous for being the easiest console to pirate games on.

Shoichiro Irimjiri claimed that the Dreamcast's logo is supposed to symbolize the "origin of power", as the universe is "like a vortex."

The PAL region logo was changed from red/orange to blue to avoid any legal conflict with German publishing firm Tivola, who also used a red swirl in their logo.

Sega made a lot of unreleased hardware for the Dreamcast including, a Dreamcast DVD Player (which was a rumored empty shell), a Zip Drive, a Swatch Access, and a VMU MP3 player.

There was a motion controller planned to release for the Sega Dreamcast. It would have been used for 'Air Nights' a sequel to 'Nights into Dreams' and was also rumored to have involved with the creation of the Sega's Super Monkey Ball series. The motion Sensing technology was eventually used for the maracas in Samba De Amigo.