For starting a discussion on metrics, I found Stevan Harnard presentation about metrics of Open Access publications very clear in describing advantages and limitations:
Are Open Access publications “proper academic” publications? New tools are challenging the monopoly of impact factors as the sole measure of research quality, but are they up to the job?
The answer to these questions seems to be different in different domains and different countries. Also many stakeholders with different objectives are involved in the discussion, with competitive interests.
Please, participate to this survey: http://www.surveymonkey.com/s/K8BBD63
Findings will be shared in this blog.