According to a leak on NeoGaf (yes I know...) the 2014 Steam summer sale begins in just eight days time, over fortnight earlier that previous years. Eurogamer had reportedly heard this same information from an anonymous source previously.
I advise everyone to contact their banks reporting their credit cards as stolen, just to stop yourself. Besides, they might as well be, Gabe sure knows how to 'steal' gamers' money (see TI4).
Personally I tend to watch these more for the mis-priced discounts as good weeklong/weekend deals tend to be more common than two years ago, however still looking forward a few games I missed last year.