Yuan Niu, Yi-Min Wang, Hao Chen, Ming Ma, and Francis Hsu
Forum spamming has become a major means of search engine spamming. To evaluate the impact of forum spamming on search quality, we have conducted a comprehensive study from three perspectives: that of the search user, the spammer, and the forum hosting site. We examine spam blogs and spam comments in both legitimate and honey forums. Our study shows that forum spamming is a widespread problem. Spammed forums, powered by the most popular software, show up in the top 20 search results for all the 189 popular keywords. On two blog sites, more than half (75% and 54% respectively) of the blogs are spam, and even on a major and reputably well maintained blog site, 8.1% of the blogs are spam . The observation on our honey forums confirms that spammers target abandoned pages and that most comment spam is meant to increase page rank rather than generate immediate traffic. We propose context-based analyses, consisting of redirection and cloaking analysis, to detect spam automatically and to overcome shortcomings of content-based analyses. Our study shows that these analyses are very effective in identifying spam pages.