For better and worse, self-reflection and meta-art is an inevitable facet of the digital age – this artist recognizes the blurred lines between physical walls and their Facebook equivalents, commenting on our relationship to social media while making light of it as well.

iHeart(StreetArt) is a street artist based in Vancouver whose creations span the spectrum from traditional tags and stencils to this series of works reflecting on our virtual lives and interactions, particularly how young people are raised in this strange new culture of communication.

He variously uses, abuses, twists and repurposes elements of our wireless language, giving hashtags and message bubbles new meaning. While he is not alone in this pursuit of geek graffiti or in using street art for social commentary, his dark humor and unique style set him apart.

This is also only a smaller sampling of a much larger body of work by iHeart which spans various street art styles as well as gallery and installation works on topics beyond contemporary digital interaction.

Somewhere between city signs and street graffiti lies a surprisingly rich and colorful language of secret messages, all hidden in plain sight on roads and sidewalks. This spray-painted slang we walk over and drive along every day is employed by infrastructure engineers, utility companies and other city workers.

Laurence Cawley of BBC News recently explored this strange world of colorful spray-painted dots, arrows, text and more, all of which denote what lies below the surface of the city.

These markings may seem rushed and crude to the casual observer, but they are essential to the protection of underground power lines, pipes and a maze of other potential subterranean hazards, as well as to the safety of those who work around them. There are no laws governing this mysterious language, simply conventions and colloquial shorthand that have evolved over time. As Cawley aptly summarizes: “Its lexicon is numbers, lines and symbols. Its grammar is most definitely colour.”

Colors are particularly critical – at least in the UK, red means electricity, blue stands for water, yellow is tied to gas, and green is used for cables (CCTV networks, television lines and fiber optics). White, meanwhile, is a kind of all-purpose color for broader communications about road and sidewalk planning. None of these are spelled out in any official manual in the UK – they are a matter of convention, and, sometimes, contention, as not all companies use the same visual dictionary.

In the United States, however, according to Smithsonian: “These ‘safety colors’–expanded to include red, orange, yellow, green, blue, purple, brown, grey, white, and black– have been formalized by the American Standards Institute (ANSI) as Safety Color Code Z535, which provides Munsell notation and Pantone color-matching information to help ensure consistency across mediums.”

Back in the UK, numbers and arrows take on different meanings depending on color and context. Sometimes they refer to the depth of a water pipe, or the pressure in a gas line. Infinity symbols may mark the end of beginning of a planned street, while zig-zags communicate an intended pedestrian crossing. Many of these are mapped out by third-party contractors whose sole job it is to locate and tag potential hazards below. All are biodegradable and many designed intentionally to fade over time.

If you are looking for more specifics, the BBC article goes into detail about the particular meanings of various individual marks, but keep in mind: many of these may be particular to the United Kingdom, or even just specific towns and streets. There is no Oxford English Dictionary tying them all together … at least not yet. The next time you take a walk, consider taking some notes as well and see if you can decipher the local dialects of this curious language on your own city’s streets.

Recently popularized thanks to TV’s MadMen, hoboglyphs also come to mind – a semi-secret language of unobtrusive markings used by the homeless to note opportunities and hazards in urban environments. And one has to wonder: are there other hidden communications out there used by ancient orders, intelligence agencies or other groups hiding in plain sight? (Images via BBC and Smithsonian)

If you long for the days when everyone in the neighborhood knew each other’s names – and business – you’ll either be delighted or horrified by Nextdoor, an app that lets you get to know your neighbors without ever actually talking to them. The app offers a private social network accessible only to those in a certain neighborhood so you can invite people to social events, find babysitters, organize a neighborhood watch or locate a lost pet.

Nextdoor can be accessed through the mobile app or on the web, with over 17,000 neighborhoods currently in its database. The idea is to connect with your neighbors to share important local information, goods and recommendations. Participants can discuss suspicious activity, share numbers for reliable plumbers, notify each other of special local events or report found items like wallets and keys. Every neighbor has to sign in with their real name and verify their address.

In an age when most people communicate through Facebook and Twitter, and nearly all of us have smart phones semi-permanently glued to our palms, apps like Nextdoor can re-forge the connection between neighbors that has degraded over time.

Some may mourn the loss of real, face-to-face interactions between neighbors, and fear that apps like Nextdoor will make it worse – but how else can you get to know the recluse on the hill who’s averse to barbecues but acutely interested in the identity of a local mail thief? Online neighborhood communities could be particularly helpful in emergency situations, as well. Check it out at Nextdoor.com.

This project tackles what is probably the last place anyone expect to find a digital-age intervention: the centuries-old tradition of the mobile and homeless communicating via shorthand markers, left to denote different risks and advantages to illicit living spaces.

From its creators at Free Art & Technology: “These stencils can be understood as a covert markup scheme for urban spaces — providing directions, information, and warnings to digital nomads and other indigenterati. We present these as modern equivalents of the chalk-based “hobo signs” developed by 19th century vagabonds and migratory workers to cope with the difficulty of nomadic life.”  (Hobo signs via Sources: Fran DeLorenzo (left),Wikipedia (right).

But it also goes beyond the conventional messages once conveyed: “Indeed, our set of QR stencils port a number of classic hobo annotations to the QR format (“turn right here”, “dangerous dog”, “food for work”) as well as some new ones, with a nod to warchalking, that are specific to contemporary conditions (“insecure wifi”, “hidden cameras”, “vegans beware”).”

As ingenious as this all is, the question, of course, remains: even in an age where almost everyone has a cellular phone, how many truly nomadic peoples have one? The answer, though, may be: more than we realize.