Surely if you purchase a domain (domain1.com) and redirect it to your existing domain (domain2.com) you expect to loose all ranking for domain1.com. 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 domain2.com in the index then you would take Rebecca's option 2 or 3.
Great information! I’m actually looking to transfer one of my websites to other domain and I wasn’t so sure which should I choose it to make the best choice. I had no idea until now that you can use an expired domain. But what are the costs of such domains? But the expired domain aren’t very expensive? Due to the fact that they belonged to websites with great daily traffic? What is the price range of an expired domain?
Finally, if you were to manually check for drop domains, you have to jump through many hoops. It's a very labor intensive and often confusing process. When you see that a domain name is available, you shouldn’t just stop there. You should also pay attention to how many backlinks it had, how niche-specific the domain is, what kind of websites link to it, did it get signals from social media, and other indicators of quality. If you were to try to look for drop domains manually, it can be a very, very intimidating process. Thankfully, there is an easier solution.
Thousands of domain names expire every day. The reasons are different. Some owners forgot to renew the domains, some just don't want them anymore or they moved on to other projects. For most people these so called Expired Domains don't have any value. They just see a bunch of Domain Names someone else deleted and move on, but for the people who know about SEO or the value of good Backlinks, Expired Domain Names are money just waiting to get picked up from the street. The only problem is to separate the good ones from the bad ones. That is where ExpiredDomains.net comes into play.