I'm only going to respond to EQnoble or people who are trying to be nice...
On paper, yes. That's true. This is typically done on forums, blogs, and other websites like it. Keyword:
Typically.
Yes. Correct. But when you have xrumer on the market, whose database does not just cover forums and blogs.. And their flexibility to derivative from their original purpose, can go into larger scope of things.
Yes, but Q&A is not restricted to forums and blogs.
I'll go into detail next point...
A database of older, well known Q&A's [once again, index] is a security nightmare.
Because, nevermind that xrumer is originally designed for forums and blog spam. Nevermind that. Take that idea and throw it out for a second.
The list [database] of Q&A's is a list telling spammers what
possible answers is to this question(s). Are we clear on that? Okay, moving on.
MATCH that database to whatever account [insert site here] retreivable account info. You now have access to the account in question. Then from there, you have access to the actual forum, social network, or website account. By large, websites require you to have an e-mail address.
Based on what I pointed out earlier:
That 850 million un-suspecting members that used generic answers to questions that should only be known to yourself... turns out to be a popular "Q&A* answer. Why? Because both the question, and the answer is in a database! Result: Many, many problems.
Yeah, this thread was about xenforo, but the thread got off topic, people assume I'm confused and the topic has to go off topic.