Steady downward trend in Google traffic conversion

[Sgt_Kickaxe]

I just looked at a chart covering the past 12 months that shows me how well traffic from Google converts and it's a steady downward slope per 1000 unique visitors.

Possibilities
#1 My site itself holds the reason for fewer conversions
#2 Traffic likely to convert isn't finding its way to my site
#3 People are buying less in general, on average
#4 Change in my rankings for any given keyword.
#5 add your reasoning here

Of interest, the traffic I received from Bing and from Yahoo both followed a different slope which is trending higher, up 2.2% over last year instead of down 12% for Google.

Is anyone else seeing any discrepancies in search visitor conversion rate between the big 3 engines?

[Shatner]

--- Google changing the format of it's search pages to draw users away from basic search data. More and more users are click int shopping, news, twitter, friend recommendation options showing up mixed in with their search query results.

[dertyfern]

I see significantly better conversions on Bing than Google for the past 6 months...don't get much Yahoo traffic.

I'm more convinced every day that Bing's results, while not necessarily better that Google's, are much more clear and don't serve to distract: people search, find, buy more readily.

[superclown2]

By the time searchers reach your site they've already trawled through countless brandspam sites so they just keep going. My Bing conversions are so good I'm optimising for that SE now with a lot of my sites.

[Whitey]

@Sgt_Kickaxe - More analytics insights are needed to narrow this down. Bounce rates , longtail , time on site , etc etc over the previous year.

Always lurking is the potential for Google to remove pages and sites that do not convert well by default - aka low quality. The trend you describe seems to reflect this - but users intent and other factors can play into the conversions a lot, as others are describing.

[mrmobility]

I don't think you can know the answer just from analytics. Have a look at the sites being returned above and just below you for your key words as well of those on PPC. Are they as good or better than your offering?