This is a little bit on the grey hat/black hat side of the spectrum. But the fact is building a blog network with expired domains flat out works. The only issue is getting those cream of the crop domains without going broke. This video will walk you through tested strategies and techniques you can use to find powerful, yet affordable, expired domains.
In today's SEO (2015) the answer would be a big no! With changes to the google algorithm and the constant updates panda, penguin, what's next...., much of the "keyword url" power is now gone. While there was a day when it made sense to buy a good named .com and expect instant indexing, not so anymore unless the site is very strong coming in ,which in that case you'll drop a minimum $50k. If you are willing to drop that kind of money and the site has a high domain authority, it might make sense as long as it matches whatever product or service that you're trying to sell. Just my opinion... 

Great article on what to look for when buying expired domains! I’ve looked at the domain and page authority of expired domains but haven’t checked if they are blocked by Google like you’ve listed. I haven’t pulled the trigger yet to purchase one (probably good that I didn’t since I didn’t do all my homework) but this will make it easier to finally go. Thanks for the great info!
Just like a property listing, except much simpler, domain marketplaces are basically massive lists of domain names that are up for sale. The process of using them is simple. Buy a domain and park it, then list your domain on the marketplace for a price you’re willing to let it go for. Once the domain is sold, the marketplace takes a cut and then passes on the remaining funds to you.
Surely if you purchase a domain ( and redirect it to your existing domain ( you expect to loose all ranking for If 301's are used then the objective is simply to pass on authority, not dominate the search results with 2 domains. If you want to keep in the index then you would take Rebecca's option 2 or 3.
You can turn then into content sites, set up an actual website, or try to sell that site elsewhere. You may even luck out by selling a site that's up and running and full of great content already. In this case, you can ask a higher price. Or, you can set up a shared hosting or direct hosting website. Shared hosting and direct hosting websites can be profitable too.

There’s an important distinction to make here between domain flipping and website flipping. The latter mainly refers to buying and selling full websites. By full websites, I mean websites that actually have content and more often than not have traffic and revenue. When buying and selling websites, the domain name matters less as the main value there is the content, traffic, revenue, history/reputation, sustainability and growth opportunities. The same can’t be said for domain names where you’re just selling “the name” and hence it’s all that really matters.