Just as honeypots are weapons against spammers, honeypot detection systems are spammer-employed counter-weapons. Newmark remains active at Craigslist in customer service, dealing mostly with spammers and scammers. Therefore, an SPF-protected domain is less attractive to spammers and phishers. Basic tools such as Captcha can prevent automatic spammers. These collected email addresses are sometimes also sold to other spammers. The redirect pages created by spammers at Interia link only to spamvertising. URL shortening may be utilized by spammers or for illicit internet activities. The simplest method involves spammers purchasing or trading lists of email addresses from other spammers. The purpose per Google was to catch excessive spammers. A few companies produce spamware, or software designed for spammers. The official reason was "developing new effective ways to combat spammers". This approach has since been adopted by many commercial spammers. The most common cause cited was abuse by spammers. Softlayer gained notoriety for hosting spammers, there were reportedly still issues in 2015.. Richter was listed in the ROKSO top 100 spammers, but is no longer included there.