Palo Alto, Calif.--AdKnowledge, a Web marketing management services company, released Monday its annual Online Advertising Report Year-in-Review. The 1999 report found that cost-per-thousand, or CPM, online advertising rates declined about 4% from a year earlier to $33.75. The report also found that the number of ad-seeking sites grew by 135% to 3,347 sites by the end of 1999. Additionally, the report found that rich media acceptance continues to grow as does banner standardization. The report compiles data from more than 3,000 Web sites. AdKnowledge is a wholly owned subsidiary of Engage Technologies, which is owned by CMGI.