Offline Saga: Is Searching In Google While Logged In Good?

Our department lab was not working for a week due to some electrical problem and I was left offline till yesterday. My spam count hit triple century and even my inbox was full. People usually get spam with Viagra, sexual strength and other such stuff. (My blog's going to get R rated! ;)) But I also get spam about watches and binoculars and there's an unusual story behind it.

Until a year ago I got only little spam with usual sex, finance themes. Then one day I searched online for watches to buy one. Two days later I got my first watch spam about a site that sold watches. I couldn't understand how that happened. Then a week later I searched for binoculars (I was on a shopping spree then... :)) The very next day a binocular spam landed. I was like 'What the hell's going on?' I searched for other things too, but they didn't materialise into spam. (I never gave my id anywhere. I was making decisions only. After selecting model I got it in retail.)  Then it hit me. On both occasions I was logged into my Google account! I still don’t understand how those people got my id. I always disabled third party cookie access too. Though I never knew how that happened, I stopped searching when I was logged in. And I no more got spam about my search queries. But my spam count has only increased. :(