Open Access News led me to this survey from the Joint Information Systems Committee (JISC) and the Open Society Institute (OSI) on authors' attitudes toward open access. Significant in the excecutive summary are the observations about citation:

The primary reason for choosing an open access outlet in which to publish is a belief in the principle of free access to research information. Over 90% of open access authors said this is important. These authors also perceive open access journals as being faster than traditional journals, having a larger readership and thus resulting in higher numbers of citations to their work. In contrast, the non-open access author group perceive open access journals as having slower publication times, a smaller readership and receiving fewer citations.

As open access gains wider reception among all researchers, note that the trend will be for authors to perceive open access as a faster way to disseminate knowledge and a way to become more widely cited. Assuming that recent trends continue in libraries having to drop subscriptions to journals, I would imagine that we could see smaller, not-for-profit journals switch to open access models to

• Promote a wider readership base.
• Cut cost by moving their journals to electronic publishing only to offset loss in revenue from reduced subscriptions.
• Increase the likelihood their articles will be cited in other publications. Researchers, after all, will be drawn to the journals which are most likely to get their articles cited since tenure and promotion is in part based on frequency of citation.