Since Google appeared, and became the most popular and frequently used search engine, things changed in the search engine industry, because the web sites began to be ranked after the number of sites that linked to them. It appears that Google considers every link that points to one site a vote for it.

Then, the link placing industry appeared, text link ads began to be bought and sold, but this was not what Google was planning, So the search engines started to filter the sites, trying to separate the ones with paid text links from the ones which earned them

It is of course,much easier to give a high ranking to your site (the number of links pointing to one site determines that site`s `page ranking` ,which is very important for the search engines) with paid text link ads, then to do search engine optimization. Text links are very popular these days, because they raise a web sites page rankings, but the fact that text link ads are becoming an industry spoils the results. Text link brokerage appeared, and if one wants to place text link ads pointing to his site, he can contact one of these brokers, or talk to the site owners.

Text links successfully blend the content, `story` , of a site with advertisements, mixing the text with the ads, unlike the too common `click here` banners. Every word in an article from a web page can become an ad now, a link to a web site. Some of these text links can be `dangerous`, because they can hijack the page you are looking at, when you click on them, or they can say that they take you to a site, but in fact they take you to a totally different one...

It is very hard to tell if bought text link ads are a good or a bad thing, because they have both advantages and disadvantages, maybe the will disappear, because the search engines filters are becoming more and more thorough, but for now the are really important in boosting a web sites rankings.