In terms of actual abortion policy, the key phrase in Obama’s Notre Dame speech (full text here) was not inspiring or poetic. It was his specific call to “reduce the number of women seeking abortions by reducing unintended pregnancies.”
In the past, Obama has rhetorically sided with pro-choice activists in saying he wanted to reduce “the need” for abortion. Pro-lifers pushed to change the language so it called for a reduction in “the number.” Obama said point blank that he wants to reduce the number.

Why does this matter? A White House task force consisting of pro life and pro choice activists has begun meeting to hammer out a “common ground” proposal. In the past, pro-choicers have said that establishing abortion reduction as a goal stigmatized women, that government should be neutral on the question of whether abortion was bad or not. Saying you want to reduce the number means you think abortion is, from a society-wide perspective, undesirable. Obama’s statement gives some moral support to the pro-lifers in the room.
It also marks for Obama a return to his campaign formulations — began in the Democratic platform — that paired abortion reduction with efforts to make it easier for women who do want to carry babies to term. Until today, Obama’s rhetoric as President had tilted in the purist pro-choice direction, somewhat leaving his pro-life allies out on a limb. Today, he climbed out there on the limb with them.
It remains to be seen what this task force will actually produce but Obama appeared to lay out the contours of the deal he’d like to see:

“So let’s work together to reduce the number of women seeking abortions by reducing unintended pregnancies, and making adoption more available, and providing care and support for women who do carry their child to term. Let’s honor the conscience of those who disagree with abortion, and draft a sensible conscience clause, and make sure that all of our health care policies are grounded in clear ethics and sound science, as well as respect for the equality of women.”

Pro-choicers get: abortion remaining legal, stem cell research loosened up, efforts get focused on encouraging changed behavior rather than legal punishments
Pro-lifers get: abortion reduction as an explicit goal, conscience clause, and an acknowledgement in abortion policy that women who want to carry babies to term should be helped just as much as those who don’t want to.
Still, all we have is rhetoric, but we may have heard today the roadmap for how that will eventually get translated into a policy compromise.
UPDATE: On re-reading the language, at Tom’s suggestion, I think I may have over-stated the significance of the wording on numbers vs. need. Dan Gilgoff at US News had a better distinction:

Though the Obama White House has been publicly quiet in recent months about its previously stated commitment to reducing demand for abortion–some aides have encouraged the news media to describe the administration’s plan for “pregnancy prevention” rather than “abortion reduction”–Obama yesterday gave a full-throated reaffirmation of his intentions to that end.
Importantly, Obama mentioned two policy proposals around abortion–increasing availability of adoption and increasing assistance to pregnant women who carry their babies to term–that go way beyond pregnancy prevention. Though the White House has carefully avoided embracing any of the Democratic legislative vehicles for reducing demand for abortion, these two proposals are enshrined in the Pregnant Women Support Act, which was recently reintroduced by Democratic lawmakers in Congress and which has won robust support from the Roman Catholic Church.