The series were originally broadcast on TV Tokyo from July 6 to September 28, 1998, and explore themes such as reality, identity and communication through philosophy, computer history, cyberpunk literature and conspiracy theory.
Serial Experiments Lain was conceived, as a series, to be original to the point of it being considered "an enormous risk" by its producer Yasuyuki Ueda. He explained he created Lain with a set of values he took as distinctly Japanese; he hoped Americans would not understand the series as the Japanese would. This would lead to a "war of ideas" over the meaning of the anime, hopefully culminating in new communication between the two cultures. Later, when he discovered that the American audience held the same views on the series as the Japanese, he was disappointed.
The Lain franchise was originally conceived to connect across forms of media (anime, video games, manga). Producer Yasuyuki Ueda said in an interview, "the approach I took for this project was to communicate the essence of the work by the total sum of many media products". The scenario for the video game was written first, and the video game was produced at the same time as the anime series, though the series was released first. A dōjinshi titled "The Nightmare of Fabrication" was produced by Yoshitoshi ABe and released in Japanese in the artbook Omnipresence in the Wired. Ueda and Konaka declared in an interview that the idea of a multimedia project was not unusual in Japan, as opposed to the contents of Lain, and the way they are exposed.
In 2009, Yoshitoshi ABe announced a spiritual sequel to Serial Experiments Lain called Despera who will reunited many of the staff who worked on Serial Experiments Lain, including Chiaki J Konaka and Ryūtarō Nakamura.
Words like "weird" or "bizarre" are almost systematically associated to review the series by English Language reviews due mostly to the freedoms taken with the animation and its unusual science fiction, philosophical and psychological context. Despite the show judged atypical, the critics responded positively to the thematic and stylistic characteristics. It was praised by the Japan Media Arts Festival, in 1998, for "its willingness to question the meaning of contemporary life" and the "extraordinarily philosophical and deep questions".
In 2005, Newtype USA stated that the main attraction to the series is its keen view on "the interlocking problems of identity and technology". The author saluted Abe's "crisp, clean character design" and the "perfect soundtrack". It concluded saying that "Serial Experiments Lain might not yet be considered a true classic, but it's a fascinating evolutionary leap that helped change the future of anime."
In 2001, Lain was subject to commentary in the literary and academic worlds. The Asian Horror Encyclopedia calls it "an outstanding psycho-horror anime about the psychic and spiritual influence of the Internet" noticing the presence of horror lore (like ghost from train accident story) and horrific visuals.
The Anime Essentials anthology, Gilles Poitras describes it as a "complex and somehow existential" anime that "pushed the envelope" of anime diversity in the 1990s, alongside the much better known Neon Genesis Evangelion and Cowboy Bebop.
In 2003, Professor Susan J. Napier, in her reading to the American Philosophical Society called The Problem of Existence in Japanese Animation. Napier asks whether there is something to which Lain should return, "between an empty real and a dark virtual".
In 2020, the review-aggregation website website Rotten Tomatoes, classified Serial Experiments Lain as one of the 25 anime TV series that have been essential to the medium over the last five decades. 
"Serial Experiments Lain helped usher in a new style of anime, of more digitally-produced shows with a glossy bloom and deeper, darker, complicated storylines. In the wake of Neon Genesis tearing up the typical anime playbook, Lain pursues a surreal, interior cyberpunk story about a withdrawn high school girl who receives an email from a classmate who has recently committed suicide. Questions of hyperreality, consciousness, and the everyday tangibility of cyberspace ensue. Lain is pretentious, symbolic, and absorbing – a prime example of a brave new world in anime."
Despite the general positive feedbacks, some negative critics stated the "lifeless" setting it had , how the last episodes failed to resolve the questions, and how the show relied so little on dialogue .
- Japan Media Arts Festival 1998: Excellence Prize 
- Producer Yasuyuki Ueda made a controversial statement made in an Animerica interview claiming Lain was somehow "a sort of cultural war against American culture and the American sense of values we [Japan] adopted after World War II".
- Despite this claim, Lain contains extensive references to Apple computers, as the American brand was used at the time by most of the creative staff.
- Konaka's Official SEL site
- Angelic Trust - Lain:Omnipresence
- Thought Experiments: Lain
- Mebious SEL Wiki