Early in the history of japanese.SE one user created an enhancement that made it easy for editors to include phonetic spelling with Han characters. It was so popular that Stack Exchange took it and made it a standard feature of the site.
In Japanese you typically add Japanese phonetic script (hiragana and katakana) to characters (known as Kanji in Japanese). This is common not just in material for learners but also for Japanese readers where it will be added just for the the obscure characters that many Japanese might not know how to pronounce. This is known as either "furigana" or "ruby text".
The same thing is not so common in Chinese text, but it's still possible. And since many of us using chinese.SE are learners who find Pinyin less difficult (though still not always easy) than Hanzi, it would still be of benefit.
It does not automatically decide the pinyin for the characters, the editor has to specifically include it using some simple formatting.
The result is that the pinyin would be displayed abover the characters, so easy to ignore for people who can read hanzi well enough. At present we right the hanzi and pinyin next to each other, or in one recent post the editor "interleaved" the characters and pinyin one-by-one, which is not very easy to read.
What do others think?
I've started a topic on the Japanese JL&U so our interested users here can discuss the feature with the users there, and see how it works. Currently it does not "just work" for Pinyin, but we might found out if they can modify it easily to work.