Factor, I use Chrome and have been through all the settings to check. I am a member of other sites and have no problem remaining logged on even when I close down my PC on an night I'm still logged on when I return. Its no big deal to have to sign back on but just thought I'd mention it in case something wasn't working properly.
I'm on Chrome too and don't have to sign in each time until after a clear-out of my cache, cookies, historyI have these settings. Maybe changing one will help.