Seems like a few trading sites are having issues with high traffic levels - not sure if that'd cause an increase OR a decrease :)
http://blogs.wsj.com/marketbeat/2012/05/18/crazy-but-true-a-...
Attention: FB order execution slowness Certain marketplaces are experiencing slowness resulting in delays in execution for Facebook orders. Industry technology teams outside of Fidelity are working to correct the problem. This slowness is being experienced by other online brokers as well, not just Fidelity. This has been reported as a market-wide issue. We do not yet know when the problem will be resolved. We appreciate your patience.