eRoi, Inc. (Portland, OR) research indicates that Wednesdays and Thursdays have the highest open and click-through rates for e-mail messages. During business hours, most messages were read at 11:00 a.m. and 4:00 p.m.

Day – Reads – Clicks

Monday – 26% – 4%

Tuesday – 23% – 3%

Wednesday – 27% – 5%

Thursday – 26% – 5%

Friday – 23% – 4%

Saturday – 12% – 2%

Sunday – 14% – 2%