Just some random thoughts, based on viewing a great deal of profiles on a 'free online dating site' which will remain nameless...
If your last failed relationship still affects you enough that you mention it in your "write about yourself" section or influences you to choose a username like "xBrokenHeartedx," you probably shouldn't be dating, online or elsewhere!
Everybody, male or female, describes themselves as "unique" or "random" - which reminds me of this XKCD comic, and Steve Martin's Nonconformist Oath. "I promise to be different! I promise to be unique!"
Many women on this site seem to be of the opinion that the best pictures for them to use are ones in which they're flaunting cleavage. I don't have a MySpace or Facebook account, so I don't know if this is common on those sites, too. As a straight male, I can't help but notice this phenomenon, and while I do look at those pictures, it doesn't make me more likely to try to contact the people who posted them. It reminds me of the female bartenders and servers who purposely dress to enhance that aspect of their bodies, presumably to earn more tips. I feel a little guilty for looking, but never guilty enough to leave a much larger tip simply based on their amount of exposed cleavage!