Most, if not all, non-scale-dependent annotation content in ADT uses annotation scaling. What that means is that the content is set up to be scaled by both the current drawing scale factor [eg, 96 for 1/8" = 1'-0"] and the current annotation plot size. Both of these are set on the Scale tab of the Drawing Setup dialog.
Content that uses annotation scaling is set up based on the fact that one unit in the content will be the annotation plot size when plotted at the scale that was current when the content was placed. Any attribute in the content that is intended to plot at the annotation plot size is one unit high in the block definition. Some content files use proportionately larger or smaller attribute heights to generate proportionately larger or smaller text. The linework graphics are drawn proportionate to the attributes.
When content that uses annotation scaling is placed, the scale factor is determined by the product of the annotation plot size and the scale factor of the current scale. So, if you have set the annotation plot size to 3/32" and your current plot scale is 1/8" = 1'-0", annotation content will be placed at a scale factor of 3/32 x 96, which is 9. Change the annotation plot size to 1/8", and the content will be placed at a scale factor of 1/8 x 96 = 12.
5/16/2005 Update: You can read a more detailed explanation of scaling in Architectural Desktop Content files in this Knowledge Base article.