I bought ten of napsters authority sites, all PR3, aged domains. I hear from someone almost every day wanting to guest post on one of my sites. I have let a few do so. What is best practice on this? I could probably post a new article a week on each site if I just accepted those coming to me but would the OBL's start to hurt me? Also I want people to leave the site via ad clicks, or following affiliate links, as opposed to going to a competitors site, but it is a good way to build content. Where's the balance? What would you do?