(CNN) -- In the early days of the Web, the mantra "information wants to be free" made the rounds. In music circles now, "music wants to be shared" seems to be the idea.
The big record labels now allow fans to play their songs free on social networking sites.
The big record labels, once more prone to awkward lawsuits against individual file swappers, now allow fans to play their songs free on social networking sites like Last.fm that use music as the social glue.
And music sharing seems ever more entwined in everyday life, sometimes in subtle ways.
Increasingly for instance it's easy to "tweet" to others what you're listening to. (A tweet is a post on Twitter, the micro-blogging site where you can broadcast to followers what you're doing, in 140 characters or less.)
For instance Skype users can opt to display, next to their names, whatever song they're playing on iTunes.
A new site called Blip.fm specializes in this, except it calls the tweets about what you're listening to "blips."
Just as Twitter asks, "What are you doing now?" Blip.fm asks: "What are you listening to now?" Then it lets anyone else hear it.
In effect, you get your own DJ space. Along with the song, you can add a comment about it. Many users now have hundreds of listeners on their Blip.fm page.
A new service called TinySong.com makes it quick and easy to share music. Just type a song's name into its search box and it creates tiny URLs linking to various sites where that song can be played right now, for free. Creating a link and emailing it to friends takes seconds.
Postcard.fm makes it an easy three-step process to create an email-able postcard combining pictures and songs from your computer.
Music sharing is growing not just online, but in the physical space as well. Some bars and clubs now have "customer DJ" nights, where a customer can dock their iPods into the sound system and play tunes for everyone else.
Copyright lawyers could clamp down on this sort of thing, says Mike McGuire, an analyst with research firm Gartner. Technically, at least. Businesses that play music to a crowd are supposed to pay a performance royalty to ASCAP, BMI or one of the other performance-rights organizations.
But they're not likely to, says McGuire: "Nobody will bother about that unless and until the clubs engaging in this become really popular."
A startup called Jook has an interesting approach to bringing music-sharing to the real world.
Earphone manufacturers can incorporate Jook technology. With Jook-enabled earphones, you can broadcast what you're playing (Us mode), and then others sitting nearby can listen in (U mode).
You'll know that they're listening to your songs by the green indicator light on their earphone cable's Jook circle, and they'll know that you're broadcasting by the red light on yours.
Jook is platform-independent, so it works even if you have an iPod from Apple and your listener has a Zune from Microsoft.
"Jook did something amazing by just saying, 'let's put this social media connection on the lanyard, make it cheap and make it multiplatform,'" says Andrew Hawn, a strategist with consumer trends research firm Iconoculture.
The way people discover music, he notes, has changed. It's no longer from a music nerd behind a counter, a la John Cusack in the movie "High Fidelity."
Anyone now can be that music nerd -- and there are ever more ways to share the music.