Aside from pre-selling your products and affiliated offers, the other purpose of your free viral report should be to build your mailing list.
This is because if you are unable to pre-sell, let alone sell, the products and services featured in your free report, the last ditch effort should be to collect leads. In short, if you cannot convert the reader into a ready buyer, you should then attempt to convert him or her into your subscriber.
In that manner, you can still follow up with your reader on future offers and have a chance at converting him or her into your customer, preferably lifetime.
You can do so by offering a lifetime update to your report or a unique notification list your reader will be interested in subscribing to, which leads to having him or her subscribed to your mailing list.