@ Oliver Mayes...
Its not as simple as Google being able to proactively decide who they are going to list in their search engine. They can refuse to sell Ascentive adwords, however to hide it from their searches would be considered a tort. (Ascentive could have a case under US tort law.) Google could be recognized by the US courts as a monopoly. (They may be a monopoly, however the courts haven't declared them a monopoly.)
If Google censors companies or websites from its index, then it would lose its immunity under I think CDA. The telcos have 'Common Carrier' status that gives them a certain amount of immunity because they don't censor their network traffic. Note that the CDA reiterates and clarifies that the immunity is strengthened by allowing them to apply filters to their network for the health of their network and systems, along with limiting 'indecent' materials.
I just googled Ascentive and voila, their website came up at the top of the list. Along with a bunch of pages indicating that the company is a scam/malware company.
I don't know if Google changed anything since the suit, or if Ascentive's complaint is that if you search on key words looking for security or anti-malware software and not containing Ascentive that they are not found. If this is the basis for their lawsuit, then they will definitely lose.
(Google's search algorithms are proprietary and considered 'trade secrets', so there could be some criteria that forces Ascentive to the bottom of the list. Its very possible that they tried some SEO optimization that google didn't like.)
Fail for the lawsuit.