If you buy keyword specific domains, you're really buying the type in traffic.  I use the URL builder and redirect through that URL so you can see how much traffic your getting from the keyword domain.  There seems to be no rythme or reason to what keyword domains deliver traffic and what don't.  By tracking traffic with the Google URL builder you get a feel for what names are giving you traffic and which are not. ie. the plural, the singular, two words, three words, the possessive, etc.

Everybody going to start using old domains should also know how to get them, I'm going to post soon article about it on seomoz as there are several ways starting from online rankings and lists up to dedicated seo tools that you can run on your computer and get precise and actual data on demand for any domains lists. Anybody intersting in such tools please visit our website: http://en.exdomain.eu/
Here's an old post on search engine roundtable that claims google's policy is to discount previous backlink juice when a domain changes ownership.  I'm not convinced whether this is actually true or something Google says to discourage excessive domain buying / 301 redirecting for SEO benefit.  The comments above seem to give varying opinions on this matter. Would be great to get to the bottom of that one!
Sellers should also learn to identify premium domain names. Dictionary names are premium domain names. Domain names with dictionary-singular names are the hottest on the Web, and buyers are willing to pay a lot to purchase them. Names, such as search.com or askme.com, will get buyers more easily than long domain names. It is also important to note that unhyphenated domain names have more value. Even product-related domain names also can enable sellers to earn substantial profit. Once a seller has a certain degree of knowledge about the domain, he can start searching for buyers.
The truth is that you require at least one year’s time to get around only the basics of the domain flipping business, leave alone making huge money from it. During this time, you’ll make several mistakes, buy useless domain names, lose out prospective deals and much more. Domain flipping is far from any get rich quick method. If overnight results are what you’re after, domain investing may not be your piece of cake. This business involves a real and steep learning curve which many people find difficult to climb.
With over 25 million .com domains registered with Google alone, this top-level domain is by far the most popular choice worldwide. According to the domain marketplace Sedo, the average sales price for a .com domain name during the second quarter of 2015 was 4,701 dollars. The most expensive publicly traded domain names have been known to fetch eight-figures. But don’t quit your day job just yet: such sales are the exception rather than the rule.

Check backlink profile: If you’re not familiar with what backlinks are, they’re basically any public website that “links” to the domain in question. Since there are numerous shady tactics in the SEO world, expired domains’ backlink profiles should be examined carefully. Check if too many links are coming from the same domain or if links have weird anchor texts/use foreign languages. You can use a tool such as ahrefs for these purposes.
There is always a learning curve in buying domains with the purpose of reselling them. Don’t hesitate to ask a lot of questions to those who went before you, participate in forums such as namepros.com and dnforum.com, keep abreast of industry trends via resources like domaining.com, and reach out to the Afternic and GoDaddy Aftermarket support teams.
What I like to do is sort by DP which stands for domain pop, and this is basically the number of linking root domains. So, BL is the number of back links. As you know that can be somewhat misleading if they have a lot of site wide links or multiple links from the same domain. I like to sort by domain pop. What that does is it brings up the sites with the most amount of referring domains.
Ur article is good but the problem is Flippas RESERVE PRICE and STart PRice are Ridiculous conflicting features.. which means sellers have no freedom to choose a good price.. But flippa gets its $10 even if seller makes $5. How shameless is this platform. Also, flippa is using a thirdparty brandable API for escrow, which allows them to charge ANY AMOUNT for escrow fee, and they are charing $25 in the name of third party. Serously flippa is a bunch of crooks
There is NO accurate way to predict the sale of digital assets – if someone wants it, they’ll buy it. For example, those wasting their money on useless .com’s (LLLL’s that have no rhyme or reason) will spend 3x more time and money optimizing their useless name as someone that buys ANY keyword loaded domain (regardless if a TLD or new one). But these individuals who are spending thousands on domains will eventually get stuck with these domains in favor of (you guessed it) the oft forgotten yet highly useful 1-3 keyword domains. Why? Study Google’s algorithm as I have for over a decade, and you’ll figure it out.
They see a domain’s price tag and they can instantly tell whether it’s under or overvalued. This is probably the most important skill one should have in this industry. Neil Patel has an interesting related quote: “The most important thing to remember when buying sites is that you always make money on the buy, never the sell.” In order to successfully do this, you must be able to spot undervalued domains. This is what will ultimately translate for you into a handsome profit margin when you get the opportunity to resell the domain for its “real value”.