[falconfunction]

So are bitcoins going to have a modifiable value based on being tainted?

[yetfeo]

blockchain.info has a method of tainting and tracking coins:

https://blockchain.info/tags?form_type=1

Taint is viewable using "Related tags" and "Taint Analysis" on address pages.

[nwh]

It's widely regarded as complete bullshit and can be fooled by almost anybody who cares to.