In the past, television has impacted — okay, influenced — presidential elections. (Clinton on Arsenio, the John Kerry “swiftboat” TV ads of ‘04.) With the emergence of the Web as THE most powerful communication tool of all time, and the public’s increasing disgust toward political ads, it is certain that social media will play a huge role in 2008.

Smart candidates will leverage social applications in interesting and effective ways. Others will fear it, not get it or just plain ignore it. So which candidate is scoring an A+ in their use of social media so far? Barack Obama. He’s using Twitter frequently, and two buzzworthy pro-Obama (prObama?) videos have popped up on YouTube. While nobody can tie these vids directly to the Obama camp, we highly suspect they’re behind it. Or at least encouraging it.

Below is our favorite, “I Got a Crush…On Obama.” Also, don’t forget to check out “Vote Different,” a mashup of Apple’s “1984″ ad and Hillary Clinton.

How else can politicians leverage social media to engage voters? The always-insightful Danah Boyd has some great suggestions.