While at the Toronto Search Engine Strategies conference a few weeks
ago I had the opportunity to attend a discussion about the potential
for malicious SEO practices, held by employees of the big 4 (Yahoo /
Google / Ask / Microsoft).

There was a general consensus between the search engines that
although malicious / negative search engine optimization could work in
concept, they have never encountered a specific case of it.
Furthermore, the representatives were sure to point out that there is
always that chance that a negative SEO campaign could have the exact
opposite of the desired effect, as building more links to site, even if
they come from a “bad area”, could have a positive net effect on
rankings.

So, what is negative search engine optimization? It’s the process
of attempting to lower the search engine rankings of a site which you
do not own / are not affiliated with (the assumption is your only able
to do off-site actions).

Negative SEO is also very hot right now - a recent Forbes article
even discusses it, although their definition of negative search is a
little looser than my own. Forbes gives 7 different forms of negative
SEO:

1. Google Bowling – creating links from “bad areas” to your
competitor’s site, thereby reducing the search engine’s impression
of the sites credibility.
2. Tattling – If the target site does any link buying / farming, one could report these to the search engine
3. Google Insulation –pushing a competitors positive news farther
down by releasing copycat news(can also be used in reverse as a defense)
4. Copyright Takedown Notices – submit fake notices to their ISP in hopes they will get their site pulled out from under them.
5. Copied Content – lower the ranking of the content on their website by creating thousands of copies around the Internet.
6. Denial of Service – take down their server by flooding it with invalid requests
7. Click Fraud – consume their advertising budgets by clicking thousands of times on their advertisements.

(A better name for Forbes’ list may have been “Negative SEO and misc. ways to get a website shutdown”)

So, how can you protect yourself?
By not making the job of the negative SEO perpetrator easier! When
building links, avoid bad neighborhoods (no 1000 links for $50.00!).
Update your content regularly to keep your site fresh, and if you see
someone copying large amounts from your site / blatantly attempt
malicous SEO, report them to google.