MiM, Man In the Middle, is the phrase of the day right now. Lenovo has been caught with their hands in the candy jar. They installed software that faked secure connections and placed ads on web sites you visited. Ads that were supposed to make money for Lenovo and likely replace ads of the webs site you went to so that they did not make any money, effectively taking the income away from them. Let me try to explain how this software is a bad thing for consumers.
In a MiM, you are contacting your bank to move some funds around. You use the HTTPS link that makes a secure connection to your bank, This protocol swaps publics keys, high security certificates, to creates a key only known to each end of the connection allowing safe and secure communication over a public internet. Now comes the MiM part, the software installed by Lenovo routes your connection to a special server that makes a secure connection to you with a low security certificate, allowing it to see your communication to the bank, and then makes a second low security connection to the bank. No one else can see the transaction with the bank, except the Man in the Middle.
The Company used by Lenovo insists they are not monitoring these communications and perhaps they are not. The problem gets bigger when you realize the low security connection they use to put ads on web sites, you go to, is so weak that it can be used by the bad guys with ease.