Coupled with the news from earlier today that desktop ad spending is decreasing, ComScore released new data that 46% of advertisements – even targeted advertisements – on websites are never seen by website visitors. This comes after more than a year of additional tracking by the company, which counts 22 of the top 25 U.S. advertisers as clients. But this new data likely comes from the fact that ComScore has reached out beyond premium ad publishers and blue-chip advertisers in the past year, and indeed many of the “lower tier” sites have in-view rates well below 50%. Nonetheless, the numbers paint an even starker picture for the world of desktop advertising and its future, especially compared to the targeting capabilities of the mobile environment.