The purpose of a search engine is to direct you to websites that are most relevant to your search and by the same token, everyone who has a website wants you to be taken directly to theirs site. Unfortunately, even sites that have nothing to do with your query, want you to land on their website first in the hopes of luring you to them. Once you’ve typed in your keyword/phrase you are taken to the SERP (Search Engine Results Page) where sites have been ranked by most relevant content according to your search. One of the factors that have a great deal of influence on SERP rankings is SEO (Search Engine Optimization). In an effort to get to the top of the “rank”, blogs and other sites will try to over optimize pages and end up leaving users to wade through useless sites until they get to what they are actually looking for.
Search engine algorithms are designed to produce results of a search according to matches of keywords as well as popularity. However since search engines can’t discern actual content, users can find themselves at blogs and sites that contain keywords but of are low quality when it comes to content. This happens when content is saturated with hyperlinks and overuse of keywords/phrases in an effort to achieve a high SERP ranking.
Luckily for the average user, Google has come up with ways to outsmart over optimization through new developments in algorithms. Of course there is no need for worry if you are using White Hat techniques in which case SEO that makes use of quality content is still the best way to increase valid SERP rankings.
So unless you are using deceptive methods like over optimizing websites or blogs, which is considered Black Hat SEO, you are safe. Remember that in the long run, White Hat techniques will always win out and getting banned by someone like Google is tough to recover from.