Can I expect that the Spanish used on the Spanish-language Wikipedia, such as this article is standard Spanish, or are they just articles originally written in English that have been translated into Spanish via Google Translate or Bing translate, etc.?
IOW, are they a good learning tool for somebody learning Spanish, or will they lead me down the garden path?
I think Spanish Wikipedia is well written. I have not found cases in which the article has translation problems or so. That Android article is cool.
In my opinion they are not translated automatically (almost) never, at least I don't do so.
Wikipedia will take you the right way.
You can acces on the tab View history up in the corner Ver historial to see changes that has been done since the first time.
http://es.wikipedia.org/w/index.php?title=Android&action=history
And on the tab discusión you can see users discussing about changes to apply to that article.
On the history you can compare two versions and looking the version between 22:50 10 mar 2014 and 09:17 11 mar 2014
You can see how someone used a very rare translator...
Honeycomb translated as Perropollo acho
Gingerbread translated as Gingerperro
http://es.wikipedia.org/w/index.php?title=Android&diff=73107869&oldid=73099948
But it is something normal, everyone can edit an article, native speakers try to edit when they see that kind of errors.
Most of the times is not a translation.
From what I know the articles are written by native speakers, they aren't the translation of other articles, if you check the articles are different across the different languages.
I use Wikipedia to see how to translate a specific terms, in my case in computer related topics.
You can see in the references, many of them are in Spanish
Automatic translations are frowned upon in Spanish Wikipedia as you may imagine. However, I find them to be more or less common, especially in articles with few editions.
They're easy to spot if they have obvious grammar errors, of course. But sometimes the choice of words and expressions may reveal that an article is (or was originally) an automatic translation. For example, if an article says that is some place "el español es hablado" (a direct translation of "Spanish is spoken") where "se habla español" feels much more natural for Spanish speakers, chances are that it was in fact automatically translated.
A rule of thumb would be to choose articles on general topics or topics well-known by Spanish speakers, because they will likely have been edited and supervised by many different authors. You can also try to go for articles that are highly rated by the community in terms of quality (artículos buenos / artículos destacados).
