How will Google find out if you are selling links?

At the Mumbai Barcamp, while talking to the audience there was a gentleman with a genuine doubt.

“Ok, so you tell me that Google will penalize you if you sell links. But how the hell would Google find it out when I’m not talking about it?”

Interesting perspective huh? So many of us are scared about the Google ban and have not sold links at all (or have not publicly told so) and there’s this guys who challenges Google asking how does it find out if he’s selling links?

There is one school of thought that says that Google traces you down from links on other websites that sells links.
Some others say that it detects you from the TLA database. (Weird!)
Even some say that Google has it’s own spider to do the job of detecting if the blog it’s on is selling text link ads.

Hmm, that sounds like lot of guesses. In fact, the last theory is pretty much believable comparing the other two. Google might have a robot or a specialized one that detects elements on a webpage that associates it with selling text link ads.

What could those elements be?

- Lot of emphasis and repetition of keywords like “Buy this ad” or “Text link for sale” etc.
- A sales page where there is a quote on the text link prices.
- Inclusion of totally unrelated, standalone, non contextual links on the site sidebar/footer.
- Presence of links to poker/pharma/porn/malware sites.
- Hosting of your website on a shared host that shares it’s IP with an already banned site.
- Excessive use of outgoing links to non contextual sites without the use of nofollow attribute.
- Public announcement of text link prices through RSS feeds/Newsletters.
- Presence of affiliate links to text link ads and brokering websites.

Dave did a better guess in finding out how easy is it for Google to find out all the websites that sold text link ads.

He says - Do this search on Google

How hard would it be for Google to write a script which basically does this…

open folder : http://www.example.com/wp-content/plugins/

Search for TLA_ which would return http://www.example.com/wp-content/plugins/tla_44565.php

Now, if that is the TLA plugin, you are doomed.

I strongly recommend all readers to refrain from practices of selling links on your websites, even if you do and want to make some cash, nofollow them so that it doesn’t corrupt the Google algorithm.