Not sure if anybody saw this yet but if you post a pin to Pinterest that links to an ecommerce site with an affiliate program, Pinterest is apparently modifying your link and adding their own affiliate code!
Read more at:
http://llsocial.com/2012/02/pinterest-modifying-user-submitted-pins/

@stewkelly I just read something interesting on that score and I’ll paraphrase just what I read :“When Pinning Doesn’t Work

Problems arise when a site just isn’t optimized for pinning. You can’t pin anything from a Flash site, which is still a favorite of many high end retailers, so that is a completely missed opportunity.”

I grabbed this info from here: http://www.searchenginejournal.com/leveraging-pinterest-how-%E2%80%9Cpinnable%E2%80%9D-is-your-content/39623/

So, it could be that if they can’t read it then they modify it perhaps, this is true for  <iframe> instances.

@casmccullough
Yes disclosure is absolutely necessary. The thing is many are unaware. It may be their fault for not wading through all the legalese (not many do) but my fear is what may happen in the future. Think about how Google is shutting down smaller players, and I don’t mean the spammy content sites either.
@devanianjali I suppose it depends on how much you appreciate other people playing around with your affiliate links. If your not making anything anyway I suppose it doesn’t matter.

and  you  cant  pin  from   facebook….anyone  know  why? and  facebook  wont let  the neat  pinterest  button on…

@casmccullough

I had the EXACT same reaction. I thought this was complete BS on Pinterest’s part, but I was surprised to see that the comments were almost entirely pro-Pinterest.

I guess I’m OK w/it, but it comes down to disclosure, and not burying it in the fine print. A simple entry in the FAQ called “How do you guys make money?” would have been perfect.

@annfurnivall

I thought that I read that Pinterest was one of the newly added apps to FB? Maybe I misread that…

What Pinterst des is similar to what Posterous did a while ago, when they started converting affiliate links without letting the users know and they eventually apologised for it.
The main problem, IMO, is not that some Pinterst users are hurt by this, nor that many are OK with what Pinterst is doing. The issue is that Pinterst did this hiding it from it’s users. It is a matter of trust, of a business philosophy and of a way of thinking.