Do the site generally need to consider the level two directory and sub-domain switch it?

Like Ask.example.com and example.com/ask,bbs.example.com and Example.com/bbs, when developing a website, do you consider switching between these two different ways of accessing each other?

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Like Ask.example.com and example.com/ask,bbs.example.com and Example.com/bbs, when developing a website, do you consider switching between these two different ways of accessing each other?

This takes into account the functionality of the site, if it is two different features implemented, in general, are made into sub-domain forms, whether for users or search engines are very friendly behavior. And once the form is determined, it is less likely to consider switching again.

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