Disappointed at some of the responses here. Especially the gratuitous insult from @ Shaisty-Chase-Tea. Mark yourself down on that one please; everyone else is..
But for those who think it's a good idea, I have to ask, if you're so needy that you have to vote up your own work, why bother posting it at all?
Why not just sit at your screen and congratulate yourself in the privacy of your own home?
Promoting yourself is one thing. Believing your own publicity is something else entirely.
But either way, promotion isn't the same as deception.
As far as I'm concerned, rating yourself as anything other than 'willing to write and receive honest feedback' is self-delusional at best, dishonest at worst.
Why compromise your personal standards for a few little buttons?