"So long and thanks for all the fish" is a reference to a book from the "Hitchhiker's Guide to the Galaxy". It is just a joking way to say goodbye.
FL was officially started on March 1, 2000. Many of us were together close to the entire time. I found the site in April of that year. The site bloomed and grew for quite a while. However, at one point the site owner returned to his home country, leaving me only his mother's phone number (which I was never able to reach). He paid the hosting fees, I paid the domain renewal and then he later returned to the site. Things were fine for a while but then in 2013, he had some things to deal with and handed over all the keys to the site to me. Unfortunately, when he made his final return last year was when things changed as others described.
For those of us who were there every day year after year, it is sad to see what happened to it.