The better quality links (From Google, Wikipedia) that a website has the higher will be its domain authority. New websites start with a ranking of one, and as the number of links increase the domain authority rises. For example, a sports website that has links to sports newspapers and sports reporting sites will have a higher domain authority than a sports website that only has links to other sports and sports blogging sites.

If you buy a domain from a 3rd party, the backlinks are valuable.  I always wait a few months before redirecting, so just set up a quick minisite until two page rank updates have passed and then go ahead and 301 redirect.  However, it seems that you'll get the link juice from the back links, the anchor text is ignored by Google.   Buying a domain at Godaddy TDName expired auctions, seem to not count as a dropped domain if you immediately set up a mini-site.
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.
When searching from keyword DHG will take your list of keywords and search each one, the pages will then be crawled to find unique domains to check availability of. The process is relatively simple but very time consuming when done manually or semi automated as was necessary in the past. Luckily now the job can be set and left to work while you do something else.
This is not the case at GoDaddy Auctions, however. There, GoDaddy starts the auction before the domain names has fully expired and the registrant does have the ability to pay a one-time restoration fee to restore ownership. This is particularly frustrating to those bidding in the auction, as you may be the winning bidder and pay your winning bid price only to find out a few days later that it was restored. You then have to wait for a refund from GoDaddy.

Hundreds of thousands of domains expire everyday. While most of them are trash, quite a few are aged domains having excellent backlinks. These can be easily filtered using metrics from Majestic (Trust Flow) & Moz (Domain Authority). These are great for your money sites or for building private blog networks. Some of these domains have natural organic traffic, that can be determined by their SEMrush rank or the SimilarWeb data. These are great for domain parking or for promoting affiliate offers.

If your domain name was in fact stolen from you, please go file a police report as soon as possible. If, instead, you allowed your domain name to expire through carelessness or ignorance, then you’ve learned a valuable lesson: domains have value. I’m not saying this to be a jerk, I’m saying this because words matter and saying something was “stolen” when in fact it was allowed to expire is not truth. I’m happy to share my knowledge as clearly as possible for others to benefit from, and all I ask is that others do the same.

Let’s just say for example we wanted this site, It looked good based on our analysis and we’d head over to Snap Names, Nameja is another one and what these service do is they have special technology on their site that allows them to try  to register a domain on your behalf over and over again. Okay? If you tried to do that your IP would get banned, but they have some system where they know how to do it just enough to get the domain, but not enough to get blacklisted.
The database also gives us the chance to analyse Whois, IP, NS, MX records and website content of every domain and to offer unique investigation and brand monitoring services for which websites like charge a lot of money. With the tools we have developed we can offer Reverse IP, Whois investigation and B2B research in bulk at a world class quality/price ratio.
Finally, we’ll look at a bit of a different animal in the expired domains world and that’s pending delete. To do that just click on the pending delete button which is right next to the Go Daddy Auction’s button. What this does is it shows you domains that aren’t quite deleted yet. So, they’re right before they get into this deleted category in expired domains. They’re going to be deleted, so they haven’t been renewed by whoever registered them, so they’re going to get dropped.
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.
Now the numbers of errors, for we give up crawling a web site in case you know, they've got some kind of anti scraping technology or the web sites just completely knackered or something thirty is generally fine. Limit number of pages crawled per website most the time you want that ticked. I have it about a hundred thousand less you are going to be crawling some particularly big websites. I like that there, because, if you have an endless, crawl and there's some kind of weird URL structure on a website like an old-school date picker or something you don't want to be endlessly stuck on that website. Show your URLs being crawled. Now, if you just want to see what it's doing, you can have it on for debugging sometimes, but I generally leave it off because it makes it slightly faster and writes results into a text file so as it goes along and it finds expired domains as well as showing you and the GUI here, you can write them into a text file just in case there's a crash or your PC shuts down or something like that.
Regarding my statement above, “Any domain name that reaches expired status and is not renewed by the owner will be auctioned by an auction service.”–it did overstretch. I’ve modified it to be: “A domain name that reaches expired status and is not renewed by the owner will be listed at an auction service (see FAQ for exception to this rule).” Then I added a FAQ to clarify. Please check my thinking:
Simple question: say I get the URL I want via auction for however umpteen hundreds of dollars, what about the renewal prices? Am I at the mercy of the auction house every year I want to renew it? Is it as simple as paying 10 or 15 bucks a year like with GoDaddy with a URL I got not through an Auction? I’m willing to pay for the desired URL up front but I don’t know what that entails down the pike.
No, no, no. ToysRUs made a perfectly logical decison that most any business would do and Google tanked them for it. ToysRUs wanted the url to direct to their site.  They're all about toys and they simply bought a url that described their business and told the url where to take people.  Google tanked them in the rankings because came with link juice. Google assumed that was doing this to manipulate the search engines but there is just, to my knowledge, ZERO evidence of this.  This is another case of Google caring more about the possible spam threat than the actual rankings for searchers.
What DomCop does for you, is show you a list of all these domains along with important metrics for every domain. These metrics, along with our powerful filtering and sorting capabilities, will help reduce the size of the daily list from 200,000+ to just a handful of the very best domains. What would take you hours, will now literally take you seconds to do.