“Today only, 84 percent off a massage!”
“Half off all garden tools!”
“47 percent off a family photo!”
If you have half a head for an online bargain, pitches like these in the form of e-mails from daily-deal vendors such as Groupon, LivingSocial, and a growing thicket of competitors are welcome messages in your inbox. Many of the sites simply require registration and, bingo, your digital world – from mobile phone to iPad or laptop – can begin to swell daily with invitations to....