The answer to that question is that "Online Consumers Open To Ads In Evening" as reported by MediaPost from an Internet Advertising Bureau and Lightspeed Research project....

"According to the research, conducted among online U.K. consumers, while the early evening was the best time of day for all age groups, younger audiences are more likely to show an increase in attention to ads as they day progressed and were more likely to prefer entertaining ads, writes Marketing Charts. In contrast, older age groups had peaks in ad interest between 9-12 pm and 2-6 pm.
The survey also polled internet users about the circumstances under which they are most receptive to ad messages. It found users are most receptive to ads when searching for deals and researching products.
Respondents are least receptive when they are enjoying an activity that requires full attention, such as watching catch-up TV or movie clips.
Specific demographic findings:
- Men and the under-age-35 age groups are most likely to say they would pay attention to online ads when researching the best deals. The over-55s are the least likely to pay attention to online ads when looking for bargains.
- When it comes to shopping online, the 25-34-year-olds are most likely to pay attention to ads: 44% say they are likely or very likely to pay attention to ads in these circumstances, and one in five say they would be very likely to pay attention to ads they saw while shopping online.
- 25 -34-year-olds are most likely to be attracted to ads while watching online video, movie clips and catch-up TV. Some 30% say they would be likely or very likely to pay attention to ads while watching video content online. The results are similar when it comes to downloading music, movies or TV shows.
In addition to various e-commerce activities, many respondents say they are likely to pay attention to online ads when engaged in a range of other pursuits, from using a search engine, to downloading entertainment files, reading the news, catching up on sports results and playing games online.
Social networking in particular has a high level of receptivity, IAB said."