If this is your goal, then you should be able to quickly establish a reasonable budget for your event, based on hiring data, and construct the event so that you can achieve your goal. The style, location and design of your event will all stem from your goal. Let's consider three types of events, each with a slightly different objective. There's nothing quite like inviting candidates to come in and meet the people they will be working with in a semi-informal session. Participants log into a specially created site to view slides and participate in a simultaneous telephone conference call.
Additional interaction is available via online limited chats and forums.
The amount of interaction with attendees is largely confined to telephone-based interaction and the number of people you can effectively manage on one conference call. Pluses include fast set-up, low fees and relatively easy access. Most models require registration of some kind. Typically these events allow for a more polished production and make it easier to accommodate larger numbers of audience members - especially if you intend to make a recorded version of the show available at a later date. Cons include a higher price point and more work in planning and hosting the event.