We all know that trust is something that is fragile in that it is very hard to earn and can be lost almost immediately when something goes wrong. We have seen it time and time again with large companies that lose their customer’s data and spend a lot of time and money trying to regain that trust.
We also see the idea of trust in a lot of the social media and recommendation based nature of many “Web 2.0” sites. Microsoft has taken advantage of reputation to increase security with Internet Explorer 9. I have set up a new machine since coming to my new job as well as several virtual machines. In all the downloads I have only had one that triggered the warnings associated with the Application Reputation feature in IE 9. When downloading an application that the SmartScreen Filter does not know about the notification at the bottom of the screen appears in red and the warning message states “<filename> is not commonly downloaded and could harm your computer”.

You are given the option to delete the download from the download list before you even begin to download it. If you want to continue with the download you must click on the actions button. This will open a SmartScreen Filter dialog that has two important clues as to why this message appeared.

One is that the download is unsigned. The other is that the SmartScreen Filter has little or no information about the download. The default action at this point is to not run the program. The other visible option is to delete the program. In either case if you are not reading what you are presented and instead just blindly click on one of the options the download will be stopped and your computer will be protected.
To continue the download you must click on the more options button. You are then presented with the following dialog.

In this dialog you are presented with the same information as the previous dialog along with the same two options to abort the download and one new option to run the program anyway. If you click on the option to run anyway you can see the download just like any other trusted download.

The nice thing about this scheme is that even for unsigned but well known downloads you are not prompted to abort the download process. Of course signed downloads that are well known you are not prompted at all so the download process is frictionless.