It also refers to vandalizing wikis, blogs and online forums with hyperlinks in order to get a higher search engine ranking for the vandal's website. Spamvertisers insert links to their websites (typically, sites purporting to sell some commercial product) and add keywords of common or related searches. The apparent goal is that a search engine will find the vandalized page full of links and improve the popularity rating of the pages to which they link. This is typically done by automated editing programs which look for editable text fields in web forms and automatically fill them in with web links. The links typically lead to pills, porn and poker sites.
Most legitimate website providers do not tolerate this practice, and will delete any site that has been spamvertised.
This practice has led to many editable online resources employing anti-spam countermeasures, including the use of captchas to prevent automated editing.