Google doesn`t link the exchange of links *link me and I will link you* . So if a random website links me and I like their material, I can`t like them back ?
Selected answers from the Dumb SEO Questions Facebook & G+ community.
Jeff Ferguson: Totally can... they just don`t like actual exchanges, which were forced and unnatural. Websites used to have these silly "partner pages" or whatever where sites would literally do the *link me and I will link you* thing and they were hilariously worthless except for gray hat SEO purposes until Google told everyone to knock it off.
Google doesn`t link the exchange of links *link me and I will link you* . So if a random website links me and I like their material, I can`t like them back ? 
