Steam Summer Sale 2015 - will start on June 11

a few Russian friends told me this year's summer sale is gonna start in 2 weeks (June 11 ) and showed me this :
VK-Steam

Google Translate:

Steam Sale starts June 11 at 20:00 Moscow time.
June 20 will begin "Sale Encore," which will involve all the companies that participated in the Summer Sale.
The very sale ends June 22 at 20:00 Moscow time.
The events and other details so far unknown.

vk is a Russian community thingy("Russian Facebook" in other words :D ) and apparently the website is legit but Steam's account there is like a group of some kind and isn't official. "It's just a group of people who gather all useful information concerning Steam like any community group. Later they were giving some proof links (like leaked e-mail screenshots) for the dates of big sales. this tiem they didn't "
thanks CrystalGamer for the info regarding "Steam Public" on VK.

but,it's not he first time these guys have leaked sale dates and other information about steam,seems liek they know what they're talking about.
http://www.neogaf.com/forum/showthread.php?t=1053299

i've backed two Kickstarter campaigns recently so i don't think i can spend much during this sale,but i'm looking forward to the events...

Update 2/6 :
so summer sale badge has appeared in the Profile Badges Page and by crafting normal badges you will get a special trading card...
at this point i'm pretty sure June 11 is the official date.