One of the most overlooked yet key components of successful romance is that it is highly subjective in nature, a reflection of, and reference to, a shared passion and history between lovers.
If your actions are such that anyone would see them as romantic, then you're doing it wrong.
This is why, so often, attached single men will remark that a given proposal story sounds crazy/lame/non-sensical, while their girlfriend is still trying to decide between sigh and swoon (go for broke ladies, if he catches you it's a good sign!).
Thus, it's possible to conduct a romantic proposal via Quora, if it makes sense for the particular couple involved, and hopefully is done in "full Quoran flair" – with much question/answer commenting, up/down voting, perhaps a special "needs improvement – should be asked on bended knee" option snuck in by a conspiratorial admin… You get the idea.
At the very least, such a proposal automatically rises above the entire pile of so-called "Jumbotronuptial Bids" incomprehensibly conducted at sports arenas in the US on a seemingly daily basis.
My advice? Follow your heart and your gut – if you think the two of you would look back on such a proposal and smile/laugh/run headlong for the nearest broom closet 10-20-50 years down the road, go for it!