Not sure if you are aware of this but I figured I would post it just in case.
I noticed when I load up my pages a reference popup in the status bar that the system was waiting to connect to b.scorecardresearch.com and would hang for a few seconds if not longer (upwards of 20sec). In researching this the b.scorecardresearch.com is considered mail-ware. More research I found disabling SEO Ultimate stopped it from happening and re-enabling it was back again.
I did some googling and found it is related to the ShareIt feature in the SEO Plugin. Looks like ShareIt uses this site for data analytics.
I disabled the ShareIt feature and it stopped happening. Too bad as I liked that feature.