What about option #4 - Redirect your existing domain to the old domain? I bought an old domain that is 100% relevant to my current domain but currently has with very little content. It did have more content fours years ago. The old domain is 13 years old, pr=3, while my current is 7 months old pr=1 and a decent amount of content. The old domain I purchased was not expired though and I do not know if this makes a difference. What are the pros and cons of option #4? Am I correct to think that option #1 would result in no benefit from the old domain's age value and if so why is it not listed as a con, a MAJOR one. Its hard to believe that a 301 using option 1 would give my existing domain 13 years credit but I'll take it if it does.
The second option requires a bit more time and effort than a 301 redirect. You could do a mini overhaul of the site and turn it into a microsite for your main domain. This option is good for exact-match domains for your targeted keyword, and there are other reasons for going the microsite route that Rand's highlighted in his post about root domains, subdomains, subfolders and microsites. This strategy also works better if the old domain has decent rankings for the keywords you're targeting.
Your domain name registrar may provide you with a free one-page Website tool, which you can use to create a “this domain is for sale” landing page. Alternatively, you can create a single page (perhaps a hidden page hanging off one of your existing websites) that indicates that your domain names are for sale. You can then forward all of your domain names that are for sale to that one page.
Many non-savvy internet users may not even be aware of the existence of other extensions. That said, because there are many new extensions popping up every now and then, you can often find amazing one word and 3-letter domain names with these new extensions that are otherwise almost impossible to find unregistered in the .com world. Additionally, these new extensions are becoming more and more familiar to users every day, hence it's almost certain that their value will continue to increase as time passes and wider adoption manifests.
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.
While buying up a ton of domains seems like a great way to make some extra money, the real world results show that it is very hard to make that process profitable. As with any industry, you will have those "golden moments" when someone you read about made it into a million dollar a year business, all while sitting in the comfort of his own home. That could be true, but he probably consumed a lot of alcohol and lost a lot of hair doing it.
Expired domains are especially attractive due to key SEO factors that are primarily associated with an existing backlink profile. If you are considering buying an expired domain, you can determine the quality of it by looking at the inbound links. When it comes to assessing the value of an expired domain relevant keywords contained in the second-level domain, a possible reference to products, brands, or services are all useful.
If you don’t have a lot of money to invest in employees and you’d rather work on your domain portfolio by yourself, you’d need plenty of free time. Generally, mini sites with 5 to 10 pages of content can be built within 5 days, while authority sites with over 10 pages could take up to two weeks. This amount of time would depend on your writing skills and knowledge of SEO techniques.
The domain name industry is quite similar to the real estate industry in a lot of aspects. There are end users, brokers, consultants and domain flippers or “domainers”. Domain flipping works similarly to buying a house, renovating it (or even sometimes just sitting on it) and then selling it again at a higher price point. The gist of it is: you’re purchasing a domain name and betting it’s worth (or will be worth) more than you paid for it. If you’re right, you get a nice paycheck and move on. Those who make a living out of this just rinse, repeat, and scale.