Microsoft denied on Monday that after a new update its Anti-Spyware program gives a preferential treatment to adware maker Claria. Until recently the program recommended users to quarantine several malware products from Claria (previously Gator), but this changed last week.
According to a statement published by Microsoft, the downgrade in threat level merely represents an effort to be "fair and consistent with how Windows AntiSpyware (Beta) handles similar software from other vendors."
In the past few days there were also rumours that Microsoft is planning to acquire Claria. More details at CNET