There's probably a much longer list than that. Part of the problem is people taking on too much.
So in my case, I've still yet to get round to altering the "Risc PC x86 card information pages" to remove surplus parts and indicate that they now only exist to provide reference information - there's unlikely to be any new development, and the x86 card is even more out of date than the Risc PC (even though some people still use both daily). Efforts to hand over to two different replacement webmasters failed.
(I think still advertising the RISC OS 2000 show beats still advertising a Christmas 2003 edition of a magazine!)
I've also relatively recently (ahem) taken over maintaining [link] from Andrew, which makes this Drobe article itself rather out of date - a gradual trickle of updates did start appearing very shortly after I finally completed my 2002/2003 tax return, i.e. nearly two weeks ago. But there's still a great deal more to do, and right now it's my top priority as far as websites are concerned.
Andrew is correct that a lot of user groups don't update the AAUG when details change. On the other hand, a lot do tell the AAUG, but have to wait a very long time for action. There even seems to have been some confusion over whether information was being acted on or not. (One disadvantage of having a webmaster in addition to a chairman!).
I long ago maintained the [link] website, handed it over to someone else (it was roughly up to date at the time, which makes a change!), they didn't maintain it, it's now been handed over to a third webmaster but still hasn't been updated. Unfortunately the onus now seems to be on me to specify what I think needs to be on the site, before anything happens. A warning that handing over responsibility doesn't always seem to mean that!
In addition, there's at least one other well known RISC OS website that now almost certainly won't get any more updates unless I do them. (I suppose this makes it my responsibility )
Throughout much of this time I was also maintaining [link] , which Martin Savage took over some time ago. This is an unusual example of a website handover that actually worked! Possibly slightly aided by the fact that getting content updated was given priority over "redesign", "relaunch", fancy new features and all the rest of it.
I think Paul Vigay possibly has similar time constraints simply in terms of the number of different websites and initiatives he's running, alongside his RISC OS day job and, well, starting up a new ISP
A fair number of user group sites also suffer from site drift - a new webmaster takes over and produces a fantastic new site, so the old website owner feels his responsibilities are complete. The old webmaster never gets round to deleting the old website from his personal webspace; and even when he closes his account, his ISP doesn't delete it, and now won't let him do it either. So old Google links to the old website keep working, which is even worse than just failing to find anything...
Speaking of Google, RISC OS related searches do quite often turn up pages that are years out of date (everyone, including me, wanted to create their own page of RISC OS links once upon a time). This means that obscure personal websites can be just as annoying as the more high profile sites listed in the article.
So, think now. Do you have a website (even a personal one) that professes to give information or links about RISC OS ? Does it need a spring clean, or does it just need to be deleted or replaced with a link to somewhere up to date?