And now for my own rant...oh...12 years after OVA was first released :P
Rayearth OVA Fandom History
It maybe hard to believe nowadays with how fast information moves around the net, but when Rayearth OVA was announced in 1996, not many people knew about it. Blogs and big Anime news websites weren't around back then and the only updated information you can rely on were magazines and Japanese websites.
When the OVA was released in 1997, many fans thought it was a continuation of where the TV series left off (the ending was kinda open ended), but when those who had access to the video started putting screenshots online, most people were shocked to see how things have changed. In addition, since it was an LD/VHS only release (DVDs were not popular yet back then), video footage was even harder to come by, and fansubs did not show up until years later. Most people relied on bootlegs, and unless you understood Chinese, you won't understand the Chinese subtitles on the bootlegs.
This was also the period of time when there was the most fan activity online: new websites starting to pop up, discussion going on mailing lists, etc. The hype starting to die down around 2000 as it's been 2 years already, but when Media Blasters announced their release of the TV series, new interest was brought to the series. Unfortunately, Media Blasters did not acquire the license to the OVA. Manga Entertainment ended up grabbing the license but only released it on VHS. It was not until 2003 (or 2002 if you imported the Japanese release) the OVA was released on DVD.
Personally I think the "Rayearth OVA boom" lost momentum to the development of digital fansubs that started to emerge in 1999-2000. Digital fansubs allowed people to get fansubs a lot faster than they traditionally had to (via tapes from local Anime clubs/rental stores/mail order/etc) and there was a bunch of new fansubbing groups appearing on the horizon since it was so much easier to create a fansub. Most groups were focused on new shows for a number of reasons, new shows have better art quality, most older shows have been licensed already and most of all, fansubbing is an ego trip (believe me, I translated for fansubs before) so releasing the newest stuff puts you at the spotlight of attention. Rayearth OVA was already 2-3 years old by then, artwork wasn't fantastic and the short story alienates those who have not seen the original series before (even though the story is standalone, you won't know the characters, not to mention most people still have not seen the second season yet).
Even today, some people still think the OVA is the third season of the TV series.
How you got to know about Rayearth OVA
To tell the truth, I can't remember. I tried looking up the old messages I kept in the mailing lists I was in back then but there were no answers there. I probably saw the bootleg VCD somewhere when I was window shopping and found out there was an OVA (mind you, bootlegs come out very fast, usually within a month of the original Japanese release). Actually when I came back to redo Rayearth OVA Dimension 4, I did some material searching online and found out a lot of new information since I know Japanese now (how it was first mentioned in 4th TV series script book, what the promotion posters looked like, what extra stuff the first LD release came with, etc). You have to love how Japanese websites tend to stay around even after years of being abandoned.
I got a strong impression from the OVA. It was the first series I watched that did not have an overall "happy ending". Most series I've watched back then (AH! MY GODDESS!, SAILOR MOON, TENCHIMUYOU, SLAYERS, MAGIC KNIGHT RAYEARTH, etc) had a happy ending, but the OVA had a "real life" ending. People do grow up and get on with life, and friends do separate. 1999 (around one year after I finished the OVA) also happened to be the year I graduated from high school and moved to Australia for university when everyone else I knew went elsewhere (Australia was not exactly the first choice for most people). I guess the OVA helped prepare me to leave "high school life" behind.
I also really liked the theme song All You Need Is Love. It's one of those few songs I still remember how to sing after all these years.