I'm referring specifically to this part:

This refers to questions such as, "What power supply should I buy?" (= off-topic). However, if you have a specific product and you want to know if it is suitable for a specific purpose ("Is this power supply okay for a Pi Zero W?"), that's fine.

So, imagine I want to ask what power supply to get. Not a great question admittedly (answers age quickly, no definitive answer possible etc.), but at least I can see how it can be helpful to newcomers once answered. Now, that question would be off-topic, but I can do the following:

  • pick a random power supply
  • ask "Is this power supply okay for a Pi Zero W?"
  • get answers. Since I picked at random, there's a good chance the "face value" answer will be NO, but there's also a good chance the answers will recommend something else

Now, instead of the initial bad question, we get an even worse question: future readers will have a harder time finding it, and it will be virtually impossible to close essentially identical questions as duplicates. This comes in addition to shortcomings the original question had.

I believe we should either allow or disallow both kinds of questions. I don't think it's feasible to prevent answers from recommending a product when the question is an obfuscated recommendation request.

2 Answers 2


I wrote the blurb on the off-topic page a while back so I would not have to keep justifying the policy, since I think it requires justification and -- yes -- to provide people with a way around it while leaving what I see as the real intent intact.

Originally it simply read:

Please note that the following is off topic:

  • Asking for specific purchasing recommendations.

Before I explain my goal here, I'll explain another related convention that's been enforced as long as the site has been around, I believe: If you are endorsing/promoting a product (hardware or software) by recommending it in an answer and you are the creater or retailer of the product, you must be honest and disclose this.

So, for example, our #1 ranked user is the author of pigpio and doesn't try to hide the fact, etc. This is fine and good.

However, occasionally people spam the site by posting a bunch of answers to questions where they recommend a product as a solution but do not disclose they stand to profit by its use. This is not so good in terms of a slippery slope to just allowing people to more-or-less use us for free advertising and so we have a policy whereby we can delete those postings.

The "no shopping requests" as I understand it is mostly there for the same reason. However, there are also a lot of potentially useful and valid questions about using products (we are, after all, a site dedicated to one). But, because you cannot just ask, "What power supply should I buy?", the most obvious way of being sneaky, asking such a question with one account then answering it with another, is cut off.

It also means we do not have a 3 year old question, "What power supply should I buy?" with 50 different answers added over time from different online retailers -- who, if they sell other Pi related products, could then go look for the "What case should I buy?" page and the "What wifi adapter should I buy?" page and the "What touchscreen should I buy?" page and so on and so on.

There's a further objection to that kind of question, namely that they are inevitably primarily opinion based -- which is why we don't allow for "What OS should I use?", even though it is not a shopping request.

Combining those two rules, it would be okay for someone selling a product to ask, "Is this power supply okay?", and then answer yes as long as they disclose they are selling it. As far as I know though, no one has bothered to do this which might be taken as evidence of the fact the policy is dissuasive.

The other thing I'd add about "What power supply should I buy?" is that it is really a question for a search engine, and there is no need for people to ask others to do that for them. At the very least, the policy means that someone must make an effort to do a search for a Raspberry Pi power supply, find one they would be willing to buy, and check here that it is really okay.

Occasionally people claim they tried to search for e.g, a microphone input but could not find any. Giving them the benefit of the doubt, the issue is either the search terms they used or that they do not understand, in this case, that pretty much any $10 USB sound dongle will work for exactly this purpose, which is why it is okay to ask "What should I look for?", which again perhaps requires slightly more effort than "Give me some product page links", but probably will produce a Q&A that is more generally useful.

This is why I made explicit the two ways around the rule -- which is how it was being enforced anyway. I think this is somewhat friendlier and more productive than just closing the questions with a link to a help page that says sorry you can't do that. Instead I'm inviting people to think a little bit, and, in the end, hopefully get help with their problem.

Now, instead of the initial bad question, we get an even worse question

I'm not disagreeing that this is possible, although it would have been good if you could find an actual example of such. I can't remember having seen one.

I would disagree in the sense that I think the normal trajectory is from a bad Q&A:

  • Q: "What power supply should I buy?"
  • A: "Buy this acme one"
  • A: "Buy the official one"
  • A: "This is the one I have, it's great"

To something which is somewhat better:

  • Q: "Is this power supply okay?"
  • A: "No, it does not provide enough amperage"

Etc. Notice again the first form is, in a context where the answers are upvoted and accepted, almost inevitably subjective/"primarily opinion based".

  • So, if I see yet another "Is my (phone charger) ok as a power supply for the RPi?", should I close it as a dupe of another question asking about a different low-amp power supply? Or am I supposed to answer, "no, not enough amps" again and again? Aug 20, 2018 at 13:51
  • A dupe does not need to be exact. Ideally there'd be a "What do I need in a power supply?" -- in fact I'm pretty sure there's one or two, I have an index for some things but not that and I'm too lazy to search right now. Another thing about things like that is they are fairly easy to answer, if you leave them for a few hours somebody will see it as an opportunity to contribute and hopefully do something reasonable. Otherwise I have to search for that dupe ;)
    – goldilocks Mod
    Aug 20, 2018 at 15:42
  • Perhaps encouraging posters to be technically objective instead of “nice” would solve few issues. This site gives an impression it is missing clear and well defined old fashioned “mission statement”. Instead of being source of technical information it seems to prefer scrutinizing peoples behavior and collecting numerous statistical data. For example recent “automated” no activity / bump info.
    – Jan Hus
    Aug 25, 2018 at 17:12
  • @JanHus Those are things you should take up on Meta.SE proper as they are beyond the scope of anything anyone here can change.
    – goldilocks Mod
    Aug 27, 2018 at 13:30

I think the power supply example over simplifies the original intent behind the distinction. A power supply should be a fairly straightforward answer, but something like a relay, motor, switch, etc may not be as straight forward. As far as I know, the original intent was for someone to draw out a plan for what they were trying to accomplish, and have the community error check an existing plan before potentially burning a building down.

I'm not sure I recall such a post ever happening though to be honest.

  • I understand the power supply is a simple example. Here's my original train of thought: I was convinced we were OK with RPi-specific recommendations before, then I saw this question being closed. I considered telling the OP to ask about a particular device instead, but then it occurred to me that seeing one question per scanner model won't make me any happier personally. Of course, I would still be happy to see questions about parameters one should consider in a scanner to be used with an RPi. Aug 15, 2018 at 7:41
  • To sum it up, I agree that questions from the scenario you described should be allowed, but I feel that the example from the help centre could incite users to obfuscate their recommendation requests instead of coming up with an elaborated plan for their specific task. Aug 15, 2018 at 7:48
  • "seeing one question per scanner model won't make me any happier personally" -> But it is more useful; it means people could check and see if a particular scanner is viable. Short of that we'd have to have "exhaustive list" type answers, which don't work very well (they often aren't really exhaustive, they easily become outdated, they provide less context).
    – goldilocks Mod
    Aug 15, 2018 at 17:22

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .