The wiki has spoiler tags and warnings for the major game secrets and things like that... as for "how people have used this" sorts of things, you will see some every time you come across an article about a complex topic like minecarts.
Some of this is good: I figured out a couple of really good pump stack designs before ever reading about how pumps work, but I would have NEVER figured out certain minecart physics exploits on my own and am glad that I got to read about them. Also, I would have not known that I could use... See, case in point -- you might not know or want to be told about my next example, so I will shut up about it.
But there are so many things.. SO many that I could only have read about. I'm not going to test every weapon type against every armor type with every kind of metal to build a matrix of their effectiveness -- but SOMEONE ELSE HAS and that is valuable. All sorts of things like this that I'm glad someone found for me so that I can play with them. Maybe if I was retired and could spend more time playing the game, I'd feel differently, but I just can't afford to discover it all on my own.
To your question though, I'd think that the forums are actually WORSE for spoilers. Not just architecture design spoilers but also major game spoilers. People tend to like to make little coy references to things which then encourages every one else to talk about it some just to demonstrate how clever they are. Especially when people say they are new and dont want spoilers.
"oh, let me be cute by using an oblique metaphor which everyone will then jump in on and expand upon". This sort of thing happens a lot.
If you want to avoid spoilers, I'd honestly recommend using the forum as little as possible.