Here's my situation, I have a site that I've owned for the past 5 years, that ranks well for my primary keyword. All of a sudden, another site comes out of the blue and gets great rankings. I was curious as to how they did this, and found that they were able to get some high PR links on edu (professors) pages because of related content, as well as some blog/forum spam.
I figured they must have emailed these edu sites and asked for the links themselves. So I did the exact same thing, politely emailed them, and got my site linked as well.
After that my site went back to #1, and his #2. Out of the blue today, I get an email from my competitor threatening me. He basically accuses me of stealing his secret link sources by looking them up in Google. So to the point, he says if I don't ask for ALL of them to be taken down he is going to do everything he can to get my site penalized or even blacklisted by Google.
He goes into a little more detail saying how Google recently changed its algorithm so that sites that participate in certain types of content farms, blogspam, and forum spam then the site will be penalized, and if I don't remove the links he says I 'stole' then he'll make sure my site is penalized or banned. To be clear, my site is 100% organic, and 100% white-hat. So now I'm worried that if someone else starts up some serious black-hat stuff that I'd be penalized.
Now he didn't include which site he belonged to and the email didn't come from his domain, but it is blatantly clear.
I was always under the impression that Google wouldn't penalize you for any incoming links, but would just make them basically worthless. I read up a bit more today about the recent changes at Google and am getting mixed messages, it almost makes it seem like it would be possible for him to do this to me.
If this is indeed the case, what is to stop everyone from doing this?
I'm not going to take the links down either way. I don't appreciate being threatened in this way. But am still worried that this is even possible.