Why not just have 1 tag or 3 tags? Or have 10, 20 or 30?

  • 8
    Why is the drinking age in many states in the US 21 and not 20, 18, 25 or 30? It's just an arbitrary limit you have to draw a line somewhere. Nov 2, 2010 at 6:38
  • 2
    @Kop Most arbitrary limits have some reasons behind them. Even if these reasons are not of most importance. 5 probably wasn't chosen by dice roll... or was it ?
    – DrDro
    Nov 4, 2010 at 10:36
  • 1
    @DrDro: it was probably chosen over 10 because 10 is too many tags, and over 4 or 6 because it's a nicer number Nov 5, 2010 at 9:44

4 Answers 4


[some] [users] [already] [abuse] [tags] [pretty] [badly] [and] [allowing] [more] [would] [only] [make] [things] [worse] [.] [besides] [,] [there] [should] [be] [some] [kind] [of] [limit] [right] [?]


I think it was to prevent under-categorizing and over-categorizing. With fewer than 5 tags you're hurting the visibility for the subject. I can ask a question that encompasses [java], [maven] [maven-repositories] [java6] and [best-practice] and have those all be legitimate tags for the subject that I'm asking about. It's helpful for people searching/subscribing to a tag and for other generic searches. Limiting it would hurt searchability of a question.

More than 5 and most questions end up being shotgun tagged to abuse its visibility. Many times on SO I see questions tagged with the top 5 most discussed languages when they really only vaguely talk about them (and a [language-agnostic] tag would be better or don't even talk about them at all). Expanding it would only lead to abuse.

So why 5? Because it strikes a nice balance.


Screen Space.

  • 7
    The final frontier. Nov 2, 2010 at 7:19

The real answer here is obvious: it's a limitation. Either cost-savings or otherwise. I don't believe the SQL back-end handles these very well.

There are certainly a lot of cases where this matters, take for instance on dba.stackexchange.com. Because we don't have hierarchical tags we tag versions. Something like PgAdmin is a tool that itself has a version. PgAdmin 4 was a total rewrite of PgAdmin 3. PgAdmin itself connects to PostgreSQL. PostgreSQL has its own version.

  • So we have [pgadmin], and [pgadmin-4]. Both of which could be applicable.
  • And, we have [postgresql] and [postgresql-9.2]. Both of which could be applicable.

Let's say now you're working on a problem that involves spatial clustering. Well now you pick,

  • [spatial]
  • [postgis]
  • [index]

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