Via Zero Hedge.
The current uptrend is presumably due to the Tucson, Arizona shooting – either out of concern for violence or concern that new gun control laws might be pushed through Congress after the incident. The #1 city searching for the phrase is Phoenix, Arizona.
I think most people would agree that the reason for the 2008 uptrend was the election of Barack Obama. Obama is an anti-gun politician whose platform included gun control laws, and specifically a new assault weapons ban. For a while it was hard to get your hands on big magazines and guns like the AR-15 that were affected by the previous AWB. If you found them the prices were sky high.
Does anyone have a clue why there was a brief, intense spike in early 2007? There must have been something big in the news, but darned if I can remember what it was.