I say "invested" because there is no actual investment with "The DAO". "Investors" are free to withdraw their funding back at any point before a proposal voting takes place. This is basically a risk-free proposition - "invest" your funding now to join on the buzz train, and take your money back at any point if you don't like the proposals being proposed. A majority vote within "The DAO" cannot actually vote for an investment with the entire funding available for "The DAO".
Technically speaking, until after some proposal wins a majority vote, no money actually changes hands... the investors are still in full control of their money and should still be considered the owners of it - not "The DAO".
For this reason, I think that calling this "the biggest crowd-funding ever" is incredibly misleading. There is no commitment and no risk, unlike how crowdfunding usually works.
Somewhat related: "Ethereum Contracts Are Going to Be Candy for Hackers" http://vessenes.com/ethereum-contracts-are-going-to-be-candy... HN discussion: https://news.ycombinator.com/item?id=11725624 (192 points, 6 days ago, 83 comments)
https://daowiki.atlassian.net/wiki/display/DAO/Step-by-Step%...
I think a large portion of the investors would be unwilling to do this and simply sell their The DAO tokens on an exchange, thereby keeping their ethereum locked up in The DAO
So, there is some risk in terms of temporarily lost liquidity, but I would still stay that comparing this to a traditional crowdfunding where investors actually lose control over their funds is nonsensical.