The 2007 impact factors were announced in the 2007 edition of ISI's Journal of Citation Reports. Zootaxa's impact factor was 0.691 in 2007. It is a small increase over the impact factor of 0.612 in 2006. Despite the factor that the number of citationsin Zootaxa increased rapidly late last year, the total number of papers in 2006 also increased rapidly (1020 papers in 2006 versus 575 papers in 2005). Thus the combined total number of papers in 2005 and 2006 is much greater than that for 2004 and 2005. Given the huge number of papers published in Zootaxa each year, the impact factor (as an average number of citation in the current year to papers published in the past two years) will likely to increase only slowly. Publication of more large and comprehensive papers will likely help to improve the average number of citations. In the last two years, Zootaxa published over 50 monographs (papers of 60 or more pages) each year. As one of the few series that can accommodate monographs, Zootaxa will likely to publish more monographs each year and these will help to improve the overall citation of the journal.