That's just a bunch of FUD. Tainting coins has not worked once in Bitcoins history.
That depends what you mean by worked. If the reports of a blockage of btc-e transactions are correct (I'm not really sure) then people were inconvenienced by the mere attempt to sort through tainted coins, whether or not that attempt was successful. As long as people believe BTC has taint then maybe that perception itself is a problem? This is not the first and won't be the last time we've heard about the concern.
there have been multiple attempts to taint BTC's over the years. all have failed. to be clear, i don't condone theft in any way, but the fact of the matter is that Bitcoin IS fungible for all the reasons i've stated above. it has to be to survive. just like USD's are fungible. sure the gvt can issue warnings for certain serial #'s on dollar bills but that is a limited and a non-scalable act (probably purposely). tainting just a few BTC would eventually taint the entire supply of existing BTC as demonstrated in Taras thread i linked to above. it is scalable and therefore dangerous to Bitcoin. tainting is not practical either as just a few hops obfuscates ownership quite effectively w/o extreme degrees of detective work:
http://trilema.com/2014/guidance-there-is-no-such-thing-as-bitcoin-taint/any gvt that subscribes to the notion of tainting will only exclude themselves from the growing Bitcoin economy as there will always be gvts somewhere that will allow those coins through either b/c of better understanding of how distributed systems over the Internet work or b/c of greed.
In any case, I have to agree with iCEBREAKER that LTC is irrelevant and the more interesting question is other coins that are actually different from BTC in meaningful ways.
i disagree. when the #2 cryptocurrency goes down that sends a big message. this assumes of course that Bitcoin is "good enough" or that it can be adaptable in the future.