Ease of use
Lower barrier to entry (therefore potential for higher participation)
Potentially more cost effective
With proper safeguards, this could add rigour to the process and prevent fraud
Quicker turnaround of results
By running this online, information about the subject being voted upon can be provided alongside or preceding the voting form page. The public could therefore be better informed of the facts of the matter there and then (at the time of their vote), as opposed to searching for the information in advance or having just one subjective view provided to them by e.g. the newspaper they read.
Ability to vote wherever you are, on any connected device.
Lower barrier to entry may mean voting isn't taken as seriously
Without proper safeguards in place, the potential risk of fraud or misuse of data may be higher
The provision of information on a subject would need to be fully unbiased and clear for all voters
There is a risk some voters may be alienated - other methods of voting would need to remain fully available
Risk of technology failure
There would need to be a real drive to separate the formal voting process from simply filling in a form or answering a poll or petition online. It would need to be clearly delineated.
Support for online voters may require quite a lot of resource (technological, phone help, email support etc)
Hosting environment would need to be absolutely watertight and this would be a large-scale undertaking
Protection for voters needed when using public wifi