If you're going to buy them to block an OG, might as well have them redirect to your site, and make them useful. We have 7 domains, and they either redirect to our main, or have to a carbon copy website of our mainsite. We also have a wedding-coordinating website that has multiple sites redirecting, as well as a link from our main sites. My wife is an IT pro, and we come up in the #1 & #2 spots in searches consistently. Meta-tags are the key, but it also seems how frequently your page is updated has something to do with listing location. Nothing worse than folks who spend huge sums of $$$ on a web design and hosting, etc., only to let it sit and collect cyber-dust.
We took over all of our websites from the wire services, and traffic has actually increased, and it costs us about $200/year to manage it ourselves, rather then paying them $70-100/month.