The best way to present your present is to be present and surprise your guest of honor.
A great way to reveal the tribute gift is to include a print out of the invitation emails in with your greeting card.
As your guest of honor reads them they will slowly come to realize there is a website somewhere out on the internet with thoughts, feelings, memories, and well wishes just for them, all compiled by you!
You'll see them light up with anticipation about what they'll find there. This is a great emotional reward for you, the presenter.
Soon as they realize what's waiting for them, get them in front of a computer with internet access and gather all the guests around, if you haven't already. You can go to the tribute website earlier and be prepared if the computer is in another room, or you can bookmark the website for a quick click on a computer in the same room. You can have somebody bring a notebook computer to the party and when you give them the signal they can sit across from the guest of honor at a table or somewhere where they are facing them. They "need to look something up" if they're asked what they're doing. Then your shill can open the notebook so the back of the screen is facing the guest of honor. When your special someone starts fidgeting because they want to go see the tribute website, your friend with the notebook can just turn it around 180 degrees so the screen is facing the guest of honor.
Make sure you ask for the tributes to be read aloud so everyone can share in the experience.