So gatherer says conspiracy cards are legal in all formats, typo?
Uhh you think!
"Conspiracy features 210 black-bordered cards, including randomly inserted premium versions of all cards in the set. There are sixty-five new cards in Conspiracy. Fifty-two of the new cards will be legal in Legacy and Vintage; thirteen cards will not."
No problem...
http://www.wizards.com/magic/tcg/productarticle.aspx?x=mtg/tcg/conspiracy/productinfo
Conspiracy is like commander.
Can be used in commander, legacy and vintage formats.
Conspiracy cards can only be used in draft situations (cubes)
So, to be explicitly clear and avoid any confusion, the thirteen cards being added to the Vintage and Legacy banned lists are:
Advantageous Proclamation
Backup Plan
Brago's Favor
Double Stroke
Immediate Action
Iterative Analysis
Muzzio's Preparations
Power Play
Secret Summoning
Secrets of Paradise
Sentinel Dispatch
Unexpected Potential
Worldknit
Hopefully, now that you've seen some of the cards, you understand just how warping they would be, and it will come as no surprise that we are formally announcing the banning of all thirteen cards of the conspiracy type from the Vintage and Legacy formats. And, as a result of that, they are also banned in Commander (since all cards banned in Vintage are also banned in Commander).
http://www.wizards.com/magic/magazine/article.aspx?x=mtg/daily/arcana/1501
Lol. It's all good and your welcome.