Remem­ber mood rings? Slip one on and the psy­che­delic stone would care­fully pon­der your mood or emo­tional state and, in sec­onds, change col­ors to reflect whether you were happy, sad, anx­ious, calm, roman­tic, or, sadly, just aver­age. As kids, this “sci­en­tific” knowl­edge was power—now I know I’m mis­er­able or cheer­ful or ner­vous. But what could I do with that information?

Although my mood ring has long been packed away, this sim­ple go-anywhere indi­ca­tor seems to have a thriv­ing, high-tech cousin that’s tak­ing cen­ter stage with dig­i­tal marketers—meet mood tech­nol­ogy, rapidly emerg­ing in step with the pro­lif­er­a­tion of mobile access and inte­gra­tion. Over the last few years, many insid­ers have argued that mobile tech­nol­ogy is all but forc­ing brands to con­sider the moods of its users, more so than any other media or plat­form before it. Apple even went so far as to sub­mit a patent for a mood-targeting tech­nol­ogy, which takes into account his­tor­i­cal and con­tex­tual infer­ences and data to cre­ate base pro­files for users. As those users move above, below, or to the right and left of “base,” con­tent and brand mes­sag­ing can be deliv­ered, based on where that per­son is in rela­tion to his or her per­sonal norm. In other words, your smart­phone knows how you should feel, and serves up a host of offer­ings based on how far you veer from that emo­tional position.

So what goes into these mood assess­ments? Lots, includ­ing bio­phys­i­cal reac­tions and responses such as heart rate, adren­a­line level, per­spi­ra­tion, body tem­per­a­ture, and even vocal indi­ca­tors such as pace, tone, pat­tern, and per­ceived stress. If you aren’t great at read­ing peo­ple, this tech­nol­ogy will no doubt give you a run for your money in the inter­per­sonal engage­ment arena. And it also opens up an inter­est­ing eth­i­cal debate. Should I, as a mar­keter, be tap­ping into seem­ingly per­sonal or pri­vate infor­ma­tion about you so that I can drive click-throughs or make a sale?

Tak­ing it a step fur­ther, these omnipresent mood gauges will look at your inter­ac­tion with your cho­sen plat­form and device—how hard are you hit­ting the touch­screen, how quickly are you mov­ing between apps or con­tent pieces, are you click­ing fast or lin­ger­ing, and, of course, the who/what/where/when of it all: what time of day is it, where are you, and where have you been? Com­pound that with things like social media sta­tus updates, music selec­tion, and con­tent con­sump­tion, and dis­cern­ing a user’s mood sud­denly seems like a no-brainer. When your younger self slammed the bed­room door and put on loud music, your par­ents didn’t need a mood ring to know you were not happy.

At its most basic form, mar­ket­ing is about con­nect­ing con­sumers to goods and ser­vices. Dig­i­tal inte­gra­tion, tar­get­ing exten­sions, and per­son­al­iza­tion paved new in-roads, all but guar­an­tee­ing those con­nec­tions would be made when the con­sumer needed them most. Mood tar­get­ing takes that con­text to the next level, hom­ing in on moods and the spe­cific moments asso­ci­ated. What’s more, it can dig deeper on oth­er­wise accepted engage­ment metrics—did I spend all that time read­ing the blog post or search­ing for a new pair of sneak­ers because I was really that engaged, or was it because I was stuck at the air­port or in a doctor’s wait­ing room? The tech­nol­ogy knows, because it can dis­cern the enthu­si­asm from the boredom.

Beyond mobile, this type of tar­get­ing is a no-brainer for wear­able technology—I explored some of these eth­i­cal ques­tions in my series on wear­able tech a few weeks ago. It’s rumored that iWatch will have some content-delivery mech­a­nisms that are trig­gered by, in part, the wearer’s inferred mood. It could poten­tially go pretty far in that arena, with things like mood-sensing dresses that flap based on the wearer’s emo­tions, and bras that sense stress. Some of these pieces can even text select con­tacts when you’re feel­ing a bit blue.

The appli­ca­tions for mood tar­get­ing seem to fall per­fectly in line with indus­tries such as med­i­cine and per­sonal care—you know the wearer is hav­ing heart pal­pi­ta­tions, panic attacks, or par­tic­u­larly high lev­els of stress and anx­i­ety. But what about other types of tar­get­ing? If I’m feel­ing sad will my smartphone—or tablet or watch—push a coupon for ice cream? Or a great event hap­pen­ing in my area? Maybe a funny video or dis­tract­ing arti­cle I might enjoy? A sale at my favorite store? A new song from an artist I love? Is there a mar­ket for tap­ping into bad moods and giv­ing peo­ple that arti­fi­cial boost—and could rel­e­vant, almost clichéd brands ben­e­fit? Tak­ing it a step fur­ther, can these tar­get­ing devices start to learn your pat­terns and, pre­sum­ably, detect trou­ble ahead and try to deliver con­tent, offers, or even reach out to friends and rel­a­tives, help­ing to reroute your bad mood com­pletely? Or, antic­i­pat­ing you might react out of frus­tra­tion, your smart­phone could warn you not to send that email—you hit those keys pretty hard—or make that phone call, if it detects ten­sion in your voice.

If I dug up my old mood ring it would no doubt work just like it always did decades ago. It would turn vio­let and con­firm that, in fact, I’m in a good mood. When my hand gets hot—from stress or, just as likely, from run­ning up the stairs or hold­ing a cup of coffee—it would proudly tout that I was ner­vous. But with a mood ring, there would be no one stand­ing by to tell me to take a deep breath, text a friend or maybe even go for a run in new Nike sneak­ers, have a Bud Light, or, heck, even a Xanax. But, tomor­row, my phone will. And what that means for mar­keters, brands, and, espe­cially, con­sumers, is a whole new level of con­nec­tiv­ity, tar­get­ing, opti­miza­tion, and con­tent deliv­ery that’s both uncom­fort­ably omnipresent and as uniquely aligned and excit­ing as vir­tu­ally any new tech­nol­ogy has ever been. And it’ll never turn your fin­ger green either.