Anchors Cloud indicates distribution of anchors (both Phrases and Terms) in percent:
Anchor Phrases are phrases with exact match with which external pages refer to the site.
Anchor phrases could be broken into smaller category - Anchor Terms. This means, that we are looking at one-word keyword with a broad match, that is, we are exploring how frequently a certain word occurs in anchor texts.
It is to be noted that Anchors Cloud will display those anchors that matter most to you (constitute >1% usage).