Link building is a crucial aspect for SEO. SEOs have and continue to try everything to build quality links quickly for their sites and their clients. Often, the topic of buying a an expired domain - to leverage the links from that site, as opposed to starting fresh.
A HighRankings Forums thread talks just about that. A member asks, should I buy an expired domain, so he doesn't have to start from scratch.
Forum owner, Jill Whalen responds:
Google claims that they reset all backward links from a site once it has new ownership. In which case it won't do you any good.
Now, I have heard this claim before, but I have also heard time and time again that this is a valid and useful strategy. So I asked Jill for the source, since I don't remember ever hearing that from the "horses mouth." Jill stepped up and provided the source from a WebmasterWorld thread dating back to March 2003 where "GoogleGuy," an official Google representative, posted "you can get that domain into Google; you just won't get credit for any pre-existing links."
GoogleGuy's response is that Google will know the domain name expired and then reset it to start from scratch. But what if a company accidently let their domain expire? What happens with domain name transfer of ownerships? What happens when you buy a preexisting site where the domain did not expire? What happens if you change the whois information? These are all questions that have stemmed from this post and has been lingering through the SEO community.
Many SEOs still believe in buying existing sites and leaving the whois information alone. But if a domain expires, it appears Google knows about it and will note it in their database.
Forum discussion at HighRankings Forums.
Update: Matt Cutts of Google commented adding that he recently wrote a bit about this at a comment on Michael's blog, where he said:
Hey Michael! If you buy typos, I'd 301 them to your main site. Even things that you win in UDRP arbitration can be 301'ed. For example, if someone bought porngoogle.com and Google won it in UDRP, it would make sense to 301 it to your main domain.What I *wouldn't* recommend is try to register unrelated expired domains in an attempt to get those pre-existing links to count toward your domain. I would also avoid registering-and-301'ing typos of competitors' domains or other completely unrelated domains.
Pick up more of that comment (there are two) at Wolf Howl.

Comments:
Peter Davis
01/15/2008 03:43 pm
I used to buy expired domains by the bucketful, until it stopped working. Actually, to qualify that statement, it usually doesn't work, sometimes it does. As with all things, Google is not perfect at filtering them out, and yes I suppose that if a company lets its domain expire and then gets it back they may find all of their link equity is gone (haven't felt like testing that one though, lol).
Matt Cutts
01/15/2008 04:17 pm
I've talked a bit about this issue on Michael's post: http://www.wolf-howl.com/google/hey-matt-cutts-how-about-a-domain-redirection-and-consolidation-post/#comment-60743
Barry Schwartz
01/15/2008 04:25 pm
Matt, that is awesome. Thanks for letting us know about the comment. You see, it is very hard for me to follow you around the web and pick up every comment you make. I appreciate you chipping in here...
imnotadoctor
01/15/2008 05:24 pm
Thanks Matt
CVOS man
01/15/2008 10:04 pm
for those of you who are dying to know, porngoogle.com was registered in 2001 and is owned by google. one tool that will show you quality backlinks in domain names (including yahoo & dmoz) is domaintools.com. they also rate expired names for you. more: http://www.netpaths.net/blog/domain-name-backorder-tools/
Gab Goldenberg
01/16/2008 03:46 am
I wonder if Matt'll comment on my cloning expired sites idea...
Emil
04/25/2008 08:46 pm
Hi, I can tell you this. If you backorder expired PR7 website, Google does NOT erase anything at all. Last week I backorder expired PR7 domain name, no website included. That specific domain was expired 35 days ago and it still holds solid PR7. So whowever said that Google will erase all backlinks when new owner register that domain is simply not right. As far as using 301 on any domains, expired or not, to bring the "good" traffic to a different website, it will NOT do you any good. You can only help your non-PR URL with good backlink from that specific domain, but that's about it.
jas blinski
08/14/2008 07:03 pm
google pageranks came from backlinks and these backlinks wont disaphere. That why the page is still valuable. I found few domains at http://www.olddomains.net/ and I get traffic right away from old backlinks.
John Green
11/25/2011 12:32 pm
I want to tell you that one of my friends who love to experiment new things in SEO, bought 4 domains which was not related to my niche at all.Then I put the content related to my niche in that.It was cached in google and it was showing the message "This site might be compromised".I think google thinks this as fishy.Please share ur view regarding this.Also I would like to tell that PR of one of the site decreased by 1 after the recent update.But the rest of all have the same PR.I would also like to know that whether sending reconsideration request will help or not in this case.