By default, Kaspersky Internet Security 2009 (KIS 2009) has its ad-blocker module enabled. This is bad for the Web, much of which is supported by advertising (and a lot of that advertising is delivered via banner ads).
I believe that the popularity of KIS is increasing, as Kaspersky's products have been hailed not only for their high malware detection rates, but also for their minimal resource utilization. This increasing popularity of KIS (and KAV - Kaspersky Anti-Virus) will lead to more banner ads getting blocked, leading to a reduction in the revenue of banner ad-supported websites, ultimately leading to either shutting down of at least some of these websites, or a reduction in the amount of fresh content (applications or multimedia or text) that the website owners add to their website (for lack of funds).
More importantly, such a default setting is a slap in the face of an entire business model on which much of the modern Web rests. Is Kaspersky trying to suggest that every banner ad is malicious? I don't think so. Yes, there are many malformed banner ads that are unpleasing, even annoying, but publishers who deploy ad-serving systems of networks that allow such unfriendly banner ads will automatically see reduced user visits to their websites, eliminating the need to have banner ad blockers installed at the user end.
Such a setting may resonate well with Kaspersky's potential customers (cleaner webpages, faster browsing, and increased privacy), but in the long run, it is ultimately bad for the customers.
An interesting thing to note is that disabling the Banner Ad Blocker causes KIS to throw a bright yellow warning - Your computer security is at risk. Oh really? I didn't know that banner ads could put my computer's security at risk. I do know that they can put my privacy at risk, but with secure browsers such as Opera configured to receive cookies only from the site that is visited, even the privacy threat is mitigated.
An Idea For Truly Portable Applications