With this action, volunteer editors have taken a strong stand against undisclosed paid advocacy. In addition to blocking the 381 “sockpuppet” accounts—a term that refers to multiple accounts used in misleading or deceptive ways—the editors deleted 210 articles created by these accounts. Most of these articles, which were related to businesses, business people, or artists, were generally promotional in nature, and often included biased or skewed information, unattributed material, and potential copyright violations. The edits made by the sockpuppets are similar enough that the community believes they were perpetrated by one coordinated group.
There's also a graph, done by en.wiki checkusers, showing the close relation between some sockpuppets and some anonymous edits on the deleted article.