Study cards, a digital version of the 3-by-5 index cards you used to spend hours making by hand, are a huge timesaver.

WSJ: A Textbook Case of iPad Fun With Studying

Study cards also are created for every passage you highlight.

WSJ: A Textbook Case of iPad Fun With Studying

One-third of American adults plan on sending an e-card this Valentine's Day, according to a recent study by the mobile testing company SOASTA. Digital cards are most popular with men between 35 and 44, and spouses were the most common recipients.

CNN: Bacon chocolate, e-cards and other Valentine trends

In many cases, rewards entice people whose cards were dormant to start spending, the study found.

WSJ: It's Easier to Return Those Unwanted Gifts

They suggest that the government should give green cards to all foreigners who come to America to study science, technology, engineering or maths.

ECONOMIST: Schumpeter

When family or friends were involved in elderly abuse, the study found that most cases involved forged checks, stolen credit cards, drained bank accounts, and transferred assets.

FORBES: Financial Abuse of the Elderly on the Rise, Study Finds

What's more, this study looks only at mortgage losses (ignoring, for instance, losses from defaults on credit cards or higher corporate defaults).

ECONOMIST: A troubling estimate of the costs so far

Rewards cards are used for 80% of credit-card purchases, according to a recent study by Phoenix Marketing International, a market research firm.

WSJ: The New Credit-Card Rewards Programs