Hitwise has been looking into GoCompare again and has some extremely interesting stats on how its traffic has been rising, falling and rising again over the last few months.
As you can see, the company had a good search term traffic share of 16% when it ranked number 1 for "car insurance" but that dropped to 2% during the penalty and is still less than 5% even though it is ranking in the top 10.
It's amazing to think that being number 1 for a search term only sends 16% of traffic and being 10th sends just 3 or 4%. 
Another Another interesting chart is the one below showing how paid search activity increased during the penalty period.
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5:13PM on 17th April 2008
Paying the price for questionable SEO. Just checked now and they are on page 2. Seeing as Google is meant to serve the most relevant results, why are Tesco at #2, surely a comparison is what most people are looking for when they query "car insurance", so the comparison sites should be highest?
Anyone agree?
9:46AM on 18th April 2008
Given a significant % of the population shops at Tesco awareness of their products is very high.
They are number 2 for 'personal loans' and 6th for 'health insurance'.
Out of curiosity, what questionable SEO tacticts did gocompare use?
11:56AM on 22nd April 2008
They bought a lot of backlinks very quickly which looks very suspicious to Google. If a site is seen to have thousands of backlinks overnight then its usually frowned heavily upon!
A linking strategy is important but not the be and end all of SEO. However unethically buying backlinks can be massively detrimental to your rankings.
9:32AM on 23rd April 2008
The second graph seems more interesting to me. Is it saying that GoCompare's volume of traffic from paid search increased after their natural search penalty?
If so, is that because GoCompare upped their PPC spend to compensate? Or that users, unable to see GoCompare in the natural rankings, clicked on the PPC ad instead (possibly because of offline marketing like GoCompare's high-rotation TV advertising)?
Or is the second graph just saying that GoCompare got the same number of PPC clicks they always did but that because they weren't getting the natural clicks it formed a larger proportion of their overall traffic?