Is it necessary to put up a link exchange on Blog ?

In almost every blog I've encountered , there is always an invitation for a link exchange . link exchange is very popular in Indonesia blogger , so almost every blog put it . But does it really need to be permitted by Google and put it up ?What kind of backlinks link exhange ?

Link exchange is a type of Two Way Backlink backlinks ! . What is a two way backlinks ? Two way backlinks is a two -way backlinks .How the scheme ?A blog gives links to blog B and B Blog also provide a link to Blog?
Does link exchange is allowed by Google ?With a heavy heart I say I do not like link exchange , lo really just do not like ?Yes does not mean you are allowed to perform like a link exchange with certain conditions and in certain conditions .Conditions are :" Link exchange is allowed if the two blogs have the same topic "
Well every blogger always put his exchane link in a page ( sometimes also on the homepage )On the page only contains a link and invitation for link exchange , none of the articles, posts or other than solicitation . And look at his comments always contains a link to confirm the link exchange .Remember :" Google indexes comments as part of a web article / blog "and" The use of links in comments are not liked by Google but is permitted in accordance with the articles of origin "Well so what if I hate a link exchange ?Is Link exchange ( really) useful in SEO ?PR a blog owned by the website and sometimes the article ( usually the PR dapet the article that appeared in the homepage and not the form of javascript and ajax when google PR update is in progress ) .
" Most Bloggers posted a link of their friends in a special Page Link exchange is not on the homepage "Then why on Page ? They barely had PR 0 if any , why the link dapet of 0 ? that there is only a loss because most links from PR 0 blogs instead dropping it in the eyes of Google !
Just think : for example, a blog has a PR of 5 , he gave a backlink to the page for it so pagenya got PR 1-2 , and then give a link back to the dozens of blog friends . From PR 1-2 and shared dozens of what is gained ? Even what if homepage " giver backlink to friend " PR 3,2,1 and even 0 ? Do you think it is useful ?So how to play it safe in the link exchange and so it is useful ?The answer is in the article do not page . Nice article has said as many as 500-1000 words . Well if many words , and there is a link , google will think that it's part of the article , well that's the safe way .Link exchange in the article also does not burden the visitors as he can find a similar article on another blog with different uniqueness !Now allow TrikBlogger.Net blog link exchange but in the article 

The following criteria :1 . should be similar2 . Not copy and paste from my results3 . Has a unique different from mine4 . Number of words 400 +5 . Indexed by google , and I have a link to dofollow ( I 'll link to you too dofollow )6 . PageRank has become not N / A ( 0 be , because PR 0 means the blog has a pagerank whereas PR N / 

A blog that has no pagerank )Regulations will be developed, I would make her a special page , thank you .