The popularity of long-Tail search engine optimization (SEO) brings with new security challenges: incidents of long-Tail keyword poisoning to lower competition and increase rev-enue have been reported. The emergence of cloud web host-ing services provides a new and effective platform for long-tail SEO spam attacks. There is growing evidence that large-scale long-Tail SEO campaigns are being carried out on cloud hosting platforms because they offer low-cost, high-speed hosting services. In this paper, we take the first step toward understanding how long-Tail SEO spam is implemented on cloud hosting platforms. After identifying 3,186 cloud direc-tories and 318,470 doorway pages on the leading cloud plat-forms for long-Tail SEO spam, we characterize their abusive behavior. One highlight of our findings is the effectiveness of the cloud-based long-Tail SEO spam, with 6% of the doorway pages successfully appearing in the top 10 search.