This is post number 800 for bret.
You may think you know - in retrospect - what teams like Dallas and Green Bay were thinking, but you really can't know. We DO know that the Niners didn't like Bulaga enough to be satisfied if he was what was left, and we also know in retrospect that both Denver and Miami were willing (and at least in the case of Denver looking) to move their picks.
I would be more upset to be a Jacksonville fan and find out we had an offer to trade back 3 slots and pick up an extra pick and we passed and took a guy projected to go 15 to 30 picks later! (Commentators kept making the excuse for them "well, maybe they didn't have a trading partner", but Baalke said in his press conference that he tried to trade with them.)
There's always talk about "best player" vs. "need", so when you have two players rated among the best overall on your board AND they're at a position of need, when one of them (Trent Williams) goes off the board, it's smart to start looking at options to ensure you get your guy! Last year the Niner's didn't trade up in the 2nd round, and when the last guy they had targeted got picked a couple picks ahead of them, they were left with little choice but to trade out or not get value. How many of you would hav liked getting Rey Maualuga? Of course, to me, it's better that we traded and got Mike Iupati!