While looking at Drawbacks of XeTeX/LuaTeX I asked myself if this question is not too localized. The question was "So, is there any drawback of XeTeX/LuaTeX that should stop me from switching right now?" and the first answer is still valid. But it's only a matter of time when it gets invalid. What should we do with answers that will likely become obsolete at some point?
The issue of out-of-date answers is definitely an important one. As TeX.SX gets a higher profile on TeX related searches, it's not good for the site to have a reputation for such answers.
Fortunately, the dynamic nature of the site and the fact that questions and answers can be edited at least allows some degree of control over out of date information. This is in fact a big advantage that the site has over other sources of information, especially mailing list archives and newsgroups.
There are two ways we can update information in the site.
- Edit existing answers with "Out of Date" warnings.
- Add new answers which explicitly override previous answers making clear that the new information supersedes the old.
There are a couple of potential pitfalls, however, in depending solely on new answers as a way of rectifying out-of-date answers.
- Unless the OP is still active on the site, a new answer that outlines why the existing answers are no longer valid is unlikely to be changed to being the new accepted answer.
- Depending on the number of answers a question has, new answers may not get many votes, even if they are rectifying out-of-date information and are therefore better answers.
There is no real solution to the first problem, but it's always worth adding a comment to the question suggesting that the OP accept the new answer (if that's appropriate.)
As for the second problem, active members of the site should try to upvote new answers of this sort, so that they will float at least to second place in the list of answers.
Regarding answers that are out-of-date already: If the author of the answer is still active, my first approach would be adding a comment to the answer telling the author about the out-of-date part and asking them to update the answer. This way the answer will hopefully be updated, but until then, there's already a note about the outdatedness.