Just as you need a diversity of backlink topics, you also want to shoot for a diverse set of anchor text on those sites.

In fact, Google attempted to curb the practice of too many exact match anchors with the Penguin update, but we still see this as a common issue with anchor text over-optimization.

The approach to take for establishing anchor text is to look at the % of each type of anchor text in the top ranking content you are trying to rank for.

You can assume that Google will respond well to those proportions for your backlinks if the topic is similar.

To simplify the concept, you can think about anchor text as 3 major categories: