They kept updating right to the end, even squeezing in one last chapter of Naruto for their hard-core fans, but on Monday the shadowy forces behind OneManga.com kept their word and removed all the online manga from their site.
This is not goodbye, however: Site administrator Zabi says OneManga will continue to post manga lists and series information, although it's debatable how useful that information is without the scans to go with it. Both OneManga and its competitor MangaFox (which has also pulled down most of its licensed manga) have active forums, which may keep readers coming back even without the free manga.
Meanwhile, anyone who can operate a search engine can still read plenty of licensed manga online, including weekly updates of popular Shonen Jump series like Naruto and Bleach. OneManga and MangaFox don't actually do scanlations; they are simply sites where the scanlation groups who translate those weekly chapters upload their work, to build a better audience. Several scanlation sites already have their pages prepped for this week's chapter of Naruto, and last week's is widely available.
Ironically, one of the reasons OneManga was established, according to this interview with one of their forum administrators, was to combat a site called Narutofan, which enraged readers by charging for high-quality downloads of the scanlations — again, scanlations that were made by others and intended to be distributed for free. Yet Narutofan is still up and running, making money from both the ads on its online manga reader and the paid downloads, while OneManga is gone.
Incidentally, I checked my iPod Touch app that draws from a variety of scanlation sites, and it will no longer load manga from OneManga.com. So it looks like the manga really is gone from that site.