A pilot reports exercising due diligence during his preflight but not notified of Presidential TFR. The violation was discovered during a post flight news update.

Narrative

I fly over the ocean locally for up to 12 hours in a day. I did not know that a TFR was issued for my area. I had received an e-mail alert notification from an aviation organization for the TFR in another area and the updated times also. I did not receive an e-mail alert for the TFR that affected my area from the aviation organization. I left my home at XA:00 and arrived at the airport 20 minutes later. There was no TFR notification at the gate entry. I taxied to the fuel pit and put fuel in from XA:30 to XA:50. There was no notification at the fuel pit. As I put in my fuel I spoke with the airport maintenance person and he said nothing about the TFR for the day. I departed at approximately XA:50 for a day of spotting. I was at a fixed over water location for about 8 hours. After my day of spotting I went home to my departure/home airport; which has no tower; ATIS; or AWOS. I flew in landed and went home not knowing that a TFR was in effect until I got home and read that the President was in town. I was shocked to find this out. No notifications at the airport and none from the aviation organization. I follow the rules as best I can but when I fly as long as I do; I can't always get updates when I am off shore. I can't always contact FSS until I get close to the shoreline; and when I get to the shoreline and the weather is fair; I don't need to check with FSS because I fly out of a non-towered airport and can see that the weather is fine. I did not know that TFR's can pop-up at a moments notice.