Bunch of reasons, ie: I don't have a trading background, accessing and executing trade data has a high barrier to entry regarding legal + financial, etc. It would be best executed by a company already in the game, like Sharebuilder.
TradeKing.com has something like an open portfolio. eToro.com is also doing this for ForEx as well.
TradeKing.com has something like an open portfolio. eToro.com is also doing this for ForEx as well.