Digi scrapping is scrapbooking on the computer. You build your pages just like you would in real life with a background paper, patterned paper, embellies, alphas, etc. Since it is all on the computer, you can use the elements over and over and over and over again. The possibilities are endless!!! When you get done, your layouts look much like they would if you had cut and pasted everything. I do mine through Heritage Makers and their digital tool. Then I have it published in a book. Some people use Photoshop Elements or a similiar product and then print them on their home computer or have them printed like a photo and add them to an album.
The info that Fran98765 posted is really helpful.