This is interesting and as I am seeing this over many accounts I felt it warranted a comment. Conversions are very tough to come by so far this month using Google AdWords and nearly non-existent on Yahoo.
I have a feeling that much of this behavior is tied to tax time and feel that things will open back up for advertisers after April 15th, but so far this month and starting at the end of March I have seen a consistent drop in the number of lead conversions. Yahoo seems to be hit the hardest, but Google AdWords is affected strongly as well.
Click traffic and impression traffic is still good at this point, but people are not buying at this time. AdWords works in cycles with ebbs and flows. It is the advertiser who sticks through the tough and good times that ends up with the best results. So if things are “flat” in your Google AdWords account, take heart other advertisers across many business sectors are experiencing this same trend.