Guilt Porn occurs when people fish for 're-tweets' and "shares" by embedding some sort of personal attack in their original post, causing the victim to be forced to share the message, not because they happen to agree with it, but because they feel the need to defend themselves from the attack.
This is ridiculous Guilt Porn: "If you don't share this anti-cancer message, you're selfish!", "Share This Religious image if you're a REAL MAN. Or, more commonly, "I bet 80% of you won't re-post this...".
The female equivalent of the Cock Block.
I was about to make my move on that hot guy at the bar, until that fake-titted whore corked me!