I have recently been researching the potential traffic for a seasonal Adwords campaign. When researching keywords using Google's Keyword Tool, the default option is "Keyword Search Volume" as you can see in this screen shot:

If its a seasonal campaign though - like "christmas cake" might be - the May search volume isn't much of a reflection on the number of searches that might take place in December. So what do you do?

Well - its very simple actually. The drop down box has an option to "Search Volume Trends". So you can run your seach again using that option:

And now you can see the huge spike in December searches.

I just wish they used actual NUMBERS rather than vague bar charts. Of course you can use the traffic estimator to get current traffic volumes - but of course you'd have to multiply that by the proportional difference in seasonal search volumes.