With so many ways we're influenced on a daily basis, it's often more accurate to consider your aggregate knowledge of a topic rather than your recollection of reading a story or seeing something on the TV.
I just asked myself how I feel about Obama, and my current mood is extremely positive. The main things I can recall influencing me are:
1. This wonderful cartoon:
2. His hilarious address at the White House Press Corps dinner:
3. Obama trumping Trump by making his statement about the capture of Osama Bin Laden just before the end of Celebrity Apprentice.
4. An article I read in the Evening Standard about Obama's jump in the polls.
5. A colleague telling me how cool he is.
There were probably many more messages I absorbed in the last couple of days, but these are the only ones I can remember specifically. It's interesting to note the split - two are under the control of the White House (the speech and the timing of the announcement), one is press coverage, one is a meme and one is idle conversation.
To be honest, I think I was most influenced by the meme. Is that bad?