I just prepped the text for v16n1 of Mail.Liberal-Judaism, which is the start of the 16th year of publication. This is a moderated mailing list I run to discuss Jewish issues in a non-judgemental forum. In it’s heyday, I had almost 200 issues in a volume. Last year I only had 44. Yet I still keep it around, even after 15 years.
Yes, I know there are mailing lists that are older. SF-Lovers is still around (it was one of the first mailing lists); I was on that list in the late 1970s. The older-sibling to MLJ is mail.jewish, founded in 1986 (making it 20 years old), which is a more halachic list. But still, I think 15 years is quite respectable.