It appears that the author of the site at www.advantage.online.pl (which appear to act as a referrer to Equis for sales of MetaStock) is trying to recruit people to post fake content to forums.

The domain appears to be owned by Przemyslaw Smolinski in Warsaw, Poland.

Here's the location of the strange request:
http://www.2ndproject.com/copywriting/posting-on-trading-related-forums/

and here is the post itself:

Posting on trading related forums
Posted by admin 5 September, 2008

I am looking for someone to make HIGH QUALITY posts about trading systems for Metastock. I am mostly interested in forums in Australia, but it can be also USA or other countries like India, Turkey, Thailand, Chine, Japan, Singapore, Germany, UK etc.
You will write about trading systems sold on www.advantage.online.pl. I will give you some examples of forums and posts I have done previously. It MUST NOT look as advertisement, but as a comment made by glad user. You have to know at least a little about trading, stock market, forex, technical analysis to make proper posts.

Rules:
- do not spam forum

Equis should take a serious look at their operations and consider whether they really want such a company to promote their products with their shady practices.

While I am not in our marketing department, that web site would not appear to be affiliated in any way with Equis.  They are using a URL designed for WIN Investing customers, which from my limited search has nothing to do with the web site you linked:

http://www.wininvesting.com/

That said, bringing potentially unsavory scams into the open is always a good thing, and I can appreciate you posting this information!

I think you are mistaken.

The page at:
http://www.advantage.online.pl/en-equis.html

has links referral links to purchasing MetaStock and data which are clearly there to provide them with commission.  The link goes to:
http://www.equis.com/advantagesystems

Unless "Advantage Systems" somehow refers to "Win Investing" in some way but I doubt it.

Advantage Systems appears to have been referring sales to Equis for at least 2 years now according to:
http://web.archive.org/web/*/http://www.advantage.online.pl/en-equis.html

I think Equis should consider whether they wish to continue to do business with such a company with questionable marketing ethics.

Interesting, it is very possible I am mistaken since as I said I am not in marketing.  The link you referenced redirects to something that says oldurl in it (but that could simply be because as you said they've been around for a while).  The link I was referring to is from a banner ad on their home page.

Also technically speaking there is nothing that directly links the two web sites together, though one would question why they were attempting to promote the site's custom formulas.