Over optimization can suppress rankings(True/False)?

[mobileapplication]

I would like to know whether Over optimization can suppress rankings?
Please clarify

[VladTepes]

Google discourage over optimization and would classified this as manipulation, SEO should be done naturally..

[MelbourneMarketing]

Keyword spamming, using link farms or link exchange are among the best examples of over-optimisation and these are frowned upon not just by Google but also by other search engines. This is because these tactics are known as black hat SEO and are seen as spam or a direct manipulation of SEO.

[autowasherads]

It can. If you overdo things you can run the risk of suppress ranking. Google always discourages it. Never do that.

[mikesonu]

Get a link from a domain and move on. (20 links on 20 domains > 20 links on 2 domains)Vary your anchor text often. (Over optimization can suppress rankings)
Some of my favorites over the last few months are link profile visualization, Multi-links for Firefox, and that Excel and Google Docs have hyperlink functions. (Thanks to Tom & Ben for the hyperlink protip.)