Hey, guys, sorry for the late response!
We've got designs for two primary voting types: a stake-weighted voting system where votes are weighted by how much of a token (BTS, BitUSD, etc) a user holds, and a one-person-one-vote system where each unique individual is allowed at most one vote. In the stake-weighted system, there is no need to worry about ID verification or reputation; voter opinions are attached to balances, so it's easy to count them. Note that there's no more anonymity for how you voted than there is for how big your balance is (if someone else knows balance X belongs to you, they also know the votes attached to balance X were cast by you).
One-person-one-vote (1P1V) is a bit more complex. First, the user establishes some kind of identity on the blockchain (BitShares accounts work wonderfully for this purpose) and then submits a request to one or more ID Verifier for certification that his identity belongs to a unique individual. The verifier determines by whatever means he deems fit whether the identity is indeed unique, and publishes an on-chain certification stating that the identity is unique (BitShares has a great primitive for this as well). In practice, the verifier will probably also verify other attributes such as name, gender, address, etc. in addition to uniqueness, though the values of these attributes would be kept private.
When someone wishes to create a poll, they either set up a registrar server or hire someone else to do it for them (Follow My Vote will provide this service) which allows voters to register to vote in the 1P1V poll. The registrar specifies which attributes it requires and which verifiers it trusts to certify them, then voters submit the requisite certifications from a majority of the trusted verifiers to the registrar. If the registrar is satisfied by the certifications, it allows the voter to register an anonymous voting key which is authorized to sign votes on the poll. The anonymous voting key is completely anonymous, such that not even the registrar knows which one belongs to which identity (for details on how this registration works, see my video:
https://www.youtube.com/watch?v=GcAz9mZW1_c). In practice, multiple registrar servers could be set up and a majority of them would be required to approve of the voting key as well.
We're also exploring options for a more decentralized 1P1V system, perhaps using some kind of Web of Trust model. We're not sure if this can be as scalable as the trusted verifiers design, though. We're definitely open to suggestions on this front!