What does "lifted blacks" mean? How does it affect your image? How do I do it in Lightroom?
Lifted blacks refers to the action of increasing the brightness of black areas of a raw image. This can have the effect of bringing out details in areas that previously had none, but if the blacks are too deep, it can result in visible noise.
Most raw processors have a Blacks slider, simply adjust it to lift the blacks.
Lifting the blacks means increasing only the dark areas of the image, especially the darkest shadows. You can use it to fill in blocked-up shadows, for example, if your image has enough dynamic range. That means you want to be using raw or HDRI, not JPEG.
The way you do this depends on the raw processor you're using:
For Lightroom 4 and Adobe Camera Raw 7 (Photoshop CS6) you have two main options.
If you only want to lift the blacks and leave the midtones and highlights alone, move the Shadows slider in the Tone Curve section of the Develop module to the right.
If you move the Blacks slider to the right instead, it affects overall image brightness, too. It's not the same effect as increasing Exposure, but Lightroom doesn't limit the effect to the shadows.
As you explore the tone space, you might end up getting to the same destination by many steps. You could raise exposure, then bring midtones back down with the Lights slider, for example.
For Lightroom 3 and older (or ACR 6/CS5 and older), the Shadows method also works. The Blacks slider doesn't work because that slider's behavior was changed in LR4; it can only crush the blacks, it can't lift them.
You can also use the Fill Light slider to get much the same effect. Don't get too attached to it, though: it went away in LR4, due to the improvements elsewhere.
Aperture 3 behaves pretty much like Lightroom 3: use the Shadows slider, not the Black Point slider. Aperture doesn't have the Fill Light option.
If you watch the histogram as you adjust these settings, you want to see the "mountainscape" remain mostly unchanged except at the left edge, which should crowd right. So, if you're using some other raw processor, look for a Blacks or Shadows slider, and play with it with that goal in mind.