Welcome to WebmasterWorld!
Your question and variants of it, probably constitute 10% of all posts here on this board, but
I'll take a shot at a summary:
This "hand-picking" applies to the DMOZ Open Directory Project, the Yahoo! Directory, and a few
other directories, but not to search engines. However, most search engines use these directories
as "seed stock" when they start to spider the web to build a new index. Having links from these
directories is therefore very important. In addition, Google's Page Rank algorithm assigns very
high Page Rank to these directories, and in Google's scheme, Page Rank is inherited by sites listed
in these directories.
Niether the directories nor Google will look kindly upon the submission of multiple domains leading
to identical content. Some directories will remove all of your listings if they detect domain-
spamming, and they *do* actively seek it out. In Google's case, they will remove your duplicate
entries, and leave only your highest-Page_rank site in their index. Therfore, the Page Rank you
have garnered from incoming links to your duplicate domains will be lost. Therefore, the duplicate
domains can have the effect of "diluting" your site's Page Rank, since the benefit of the incoming
links to the de-listed duplicate domains will be lost.
Extremely good results can be achieved by using multiple domains pointing to the same content, but
only until you get the "death penalty" after a few months.
The new rules seem to be: Please the end-customer, please the search engines, and please your direct
customer, in that order. Most of the "old tricks" don't work any more because the search engines
have gotten wise to them. Those tricks that still work may stop working soon. The result of trying
to "cheat the system" can be found easily here on WebmasterWorld - simply use the site search
feature here, and search for "Site dropped," "Page Rank 0," and "PR0 penalty". In many cases,
mistakes made by members who just didn't know any better have resulted in companies almost going
out of business - or worse.
Spend your time creating good, useful content, making your site user-friendly, and validating the
code on your site to W3C compliance. Use optimization techniques only insofar as they help
consumers who really want what you have to offer find you and and purchase easily. Get incoming
links from other highly-ranked sites relevant to your business (i.e. suppliers, customers, interest
groups). All else will fall into place.
Tricks are out, content is in. On-page optimization techniques (e.g. keyword density, etc.) can
still be used, as long as they don't make the language sound unnatural - remember those human
I'm sure I haven't covered more than 1% of it -- Do take advantage of the site search, Google
Knowledge base, and archives here on WebmasterWorld.
Be careful, and good luck!
<edit> See this thread [webmasterworld.com] </edit>