Although I’m not privy to the exact methods that Cheapflights used Nov-Jan, personally my money is on site redesign, upped SEM spend, and increased back-linking and referrals in the previous month. Each engine’s algorithms are different, but these factors could affect organic rank and ad visibility particularly well at Google to create the sort of spike pictured above. Specifically, Cheapflights’ site redesign launched in early 2008 and correlates with the Transfer volume spike.

Keep in mind that Cheapflights’ actions had a positive effect across all three engines but in particular Google’s algorithms and users responded well; Yahoo and MSN/Live month-over-month Transfer volume increases were about 50% each, although the bar graph doesn’t show these as dramatically. Add in advantageous organic ranking at Google (relative to Yahoo and MSN changes) and increased SEM and you’re got a situation where one engine will outpace others.

I’m not specifically looking at a paid/natural breakout in this post, although both types of traffic did grow in the timeframe examined. The idea is that becuase Search & Portal traffic spiked Nov-Jan, we can look at the top three engines and infer whether or not the traffic gains from search generated proportional transfers for Cheapflights.