>I guess they can sense I'm "damaged goods" and don't want to waste their time with me
The thing you have to keep in mind is that not everyone is looking for the same kind of friendship and what they want with people is going to vary drastically from person to person. It might have nothing to do with you being a broken individual, since these people you're trying to befriend could be getting their basic social needs filled elsewhere. So what you want out of them, is not what they want out of you.
In other words, if you're trying to befriend someone who doesn't feel (how they feel about it is really more important than how many friends they actually have) lacking in the social department of their life, you're going to naturally have a hard time trying to fit your life into theirs and make things work out in a way where you both feel fulfilled from the experience.
People are naturally already overwhelmed with all their current social connections, since it's so easy to talk to people, get what you need from them and move on, so they get stressed out and you begin to hear from them less and less, etc. So we end up in this position of where we actually shun and get shunned due to having too readily available access to social networking and it being on demand due to how easy it is to do. Thus, you end up with very shallow friendships where people will take what they can from you and tend to not give a fuck about you, because it's just simply too troublesome and counterproductive for their own personal desires (not to mention how easy it is to replace negative friends).
I'm pretty much in the same boat as you and other anons (no friends), only I've never used any sort of social networking site, I don't even use steam, so I've had the chance to really get more one-on-one with people I've spoken to. I've found the reason people avoided me socially was never due to technical personal faults (though I thought it was for the longest time), rather it has to do with them thinking about their own lives and how they can make things most convenient for themselves. So unless you're willing to shapeshift per individual to make yourself a convenient entity that they can suck the energy from in the correct circumstances, trying to make friends with people who have no interest in (or already have fulfilled the desire of) the kind of friendship you're looking for to begin with is a bad idea. But you really can't tell this about a person until you really get to know them more.
The only way you're going to make a fulfilling friendship or social contact is if you manage to find someone who feels their life is lacking and you can both fill the hole for one another. The only times I've ever managed to make friends in my life was the times where I was exactly what a person needed to fill some sort of gap in their social life. I lost all those friendships when it became apparent I could no longer fill that gap for them, or they found someone to replace me that did a better job of it.
In other words, it's not your fault, but rather it's more so case-by-case depending on who in specific you're talking to and what they believe you have for them. The more lonely a person is, the more likely you're willing to find what you're looking for. But by that same account, if that lonely person finds someone that gives them what they want easier, they'll probably toss you aside. In all technicalities this is not yours or anyone's faults; as you cannot be someone who can fill the random void according to any and all random individuals you meet.
And if they straight up call (or hint at) you too depressing, broken, damaged, whatever, don't even waste your emotional capacity on them, they have no intention to be friends with you regardless of your emotional and mental status. Those kinds of people are the kinds of people who just want to talk shit with someone easy-going then proceed to never talk to that person again. In other words, they just want an easy ride with all their conversations (including strangers), and you just dampened their mood because you didn't lift their spirit for all the few minutes they decided they wanted to talk to you. Those people aren't worth anything.
So don't blame yourself. It's not your fault, even though it's really easy to think it is since everyone else is probably blaming you. Truth be told, friendship is just something that's WAY too case-by-case and dependent on the specific individual to really blame yourself for failing to connect to them. So don't blame yourself. Don't do it. Because this is something that depends entirely on what the other person wants from you and you are not a Haruhi able to grant them any wish.
I apologize for the wall of text, by the way. I have a very bad habit of going overboard with words. I just read that one sentence and it hit me right in the feels and I exploded.