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Hello, 
I have a question that I can't find a good answer on. 
I have a site, actually a "portal"/ "directory" for service providers. 
Now, for start, we opened every service provider own page on our site, but now we get a lot of applications from those providers that thy want sites from their own. 
We want to make every service provider his own site, but on sub domain url. ( they don’t mind… its ok for them) 
So, my site is www.exaple.com 
There site will be: provider.exaple.com 
Now I have two questions: 
1. can it harm my site in SEO? 
2. if one from those sub domain , punished by google because is owner do "black hat seo" , how it will affect the rood domin? It can make the root domain to get punished? 
Thanks!!