Find a good alter-ego and stick with it.
Good meant in both senses: both in the sense of the alter-ego suiting the needs your actual ego does not have fulfilled, and in the sense of a morally positive good where the intent is to help not harm. Having an inbuilt termination as any and all human beings, is surely a cruelty enough to seek kindness and goodness. (Any argument then of existence being cruel so you must be cruel is rather childlike and playground rules: they hit you so you hit them so they hit you, add infinity!)
On the internet, not just DU, any and all representations and communications must bear in mind common sense and common decency. Just because it is online does not mean you should deceive or rage out, you have the freedom to do so but just because you can is not an effective mantra and reason to do so.
Due to the nature of anonymity on the internet, the web, online, most communication lacks the nuances and simplicity of talking to someone in person. Therefore the risk of someone being not what they present is very high and very likely, though that should not then mean everyone goes around with their guard up and suspicion at every word. Especially not when people are connected globally but still lack connection with other people. (Its not the distance but the depth that counts!)
Enough side tracking! Any member has the freedom to artistically express themselves (though with a thousand added clauses to that), but no member has the freedom to be a catfishing asshat. - Someone seeking to deceive and entice others into a relationship by adopting a false persona.
Not only is falsity a bad, negative, basis for relationships, but almost interferes with some of the basic human rights, though strangely enough there is no Human Right which deals with falsity or impersonating another person.
Ah! More side tracking!
Catfishing can be considered on par and equal to trolling, something which handily enough breaks the terms on DU:
"You may not post or transmit any false, defamatory, abusive, threatening or illegal User Content or User Content that infringes on the rights of others or the ability of others to enjoy the Site."
- and I m sure it can easily be argued that being on the receiving end of catfishing infringes the enjoyment of others and is false User Content.
A poem or profile is not false User Content, as it is true to an idea: true to the style that is adopted and mostly affects the producer not the recipient. Catfishing is false user Content, and through private messages affects a recipient equally if not more than the producer.
So to sum up: you can be false and deceiving in your poems and profiles, but should be true in your private messages. And no, being true to a personality or persona that deceives another person in order to affect them is not valid. (I can call myself a 'Lord' but have no actual documentation to back it up and am not in the habit of demanding people treat me as a Lord supposedly should be treated!)