Estimating the reach of a display (banner) ad is a straightforward process. We can tell how many times the ad was served, how many people interacted with it and how many of them clicked through.

For blogs, this task is bit more complex and at times not possible to estimate. First, a blog’s “media kit” only provides Monthly Unique Visitors (MUV). Second, there is no mechanism for tracking exactly how many people view the placement.

Some brands take a simplistic approach to estimating the reach of a blog placement. For example, some simply divide the MUVs for a blog by thirty days to get an estimate of how many visitors viewed a post when it was in the top spot on a blog. However, the daily number of visitors ebbs and flows–there be many unique visitors that frequent the site every day, but there may also be several days that do not fit a typical linear pattern.

For instance, let’s assume that a blog has 10 MUVs, and that they visit the site every time content gets posted. Even if brand’s content gets posted only once, you would still reach 10 MUVs.  If the visitors only read every other post, you would reach half. This is the reason why blogs do not give daily numbers.

Another approach would be to use a tool such as Quantcast to estimate daily visitors but given the example above it could lead erroneous assumptions. Furthermore, there are many external events that may affect a blog’s daily unique visitors.  Some events are known and anticipated. For luxury brands, it critical to secure placements during Fashion Week or on Oscar night and celebrities are dressed in designer labels—but a placement during Superbowl Sunday would likely fall flat. There are also unpredictable events that may cause certain days to have an abnormal number of visitors, whether it be higher or lower.

In my experience, the actual reach of a blog placement is closer to the monthly number than to the daily one.