Related to site layout, etc, but separate. For 17 years I’ve been using the old 468x60 ad format, since its pretty universal. However, modern layouts use a whole host of different (and less intrusive) sizes, and I would like to take advantage of that.
So, (and this is longer term), along with site layout changes you may notice our advertisers have smaller ads here and there, in addition to the big one up in the header. This is mostly to make it easier for me to make site layout changes.