Biggie has three of the Top 10 hip-hop songs between 1986 and 1999. This is a strong signal that future generations will remember Biggie as the referent artist of 80s and 90s hip-hop. And there's No Diggity as the top – perhaps it's that glorious Dr. Dre verse.

Hip hop heads will lament the omission of Rakim, Public Enemy, or Jay-Z’s Reasonable Doubt. It’s a depressing reality that exists for every genre and generation: not every artist will be remembered. The incoming generation will control what’s relevant from the 90s and carried into the future, independant of quality and commercial success. For rock, that might be Blink-182. For electronica, that might be Sandstorm.

Past popularity doesn’t always translate into present-day popularity. Here's how that manifests across all genres and decades.

For the entire 1980s, Don’t Stop Believin’ is the most-played song on Spotify. This song barely charted on Billboard. From the 70’s: Bohemian Rhapsody. If we were to time travel to either decade, no one would reasonably believe that these two songs would be cultural touchstones for their respective decades in 2015.

Over time, our biggest stars will fade, and sometimes surprising acts emerge.

Let's examine this pattern to better understand the present-day popularity of historic superstars.

Here are the top-5 tracks from the 90s, along with Billboard performance in the year of each song's release date.

For example, in 1961, Bobby Lewis’s Tossin’ and Turnin’ spent 7 weeks at #1. For all intents and purposes, Bobby Lewis was the Beyonce of 1961. Yet, have you heard of it? Do you know who Bobby Lewis is?

Meanwhile, Etta James’ debut album dropped the same year, with At Last peaking on Billboard at #68.

Music historians will regard Bobby Lewis as a pioneer in rock and roll and R&B, yet whatever led to Tossin’ and Turnin’s popularity in 1961 has faded over time. His music, for countless reasons, didn’t persevere in the same way as Etta James’.

One hypothesis: Tossin’ and Turnin’s success had more to do than just the song...perhaps Bobby Lewis was a huge personality. Great looks. Amazing dancer. When we examine pop hits, popularity is so much more than song quality.

But future generations don’t remember Bobby Lewis’s dancing and good looks. Spotify only catalogues his music. And unfortunately, that quality didn’t endure in the same way as At Last. (And of course, we have not even considered the role of covers, samples, and movie soundtracks, etc. – a future project to undertake).

And for this reason, it will be weird to hear future generations reverently listen to groups such as Nickelback – the kids only know their music, not what they culturally stood for in 2015.

Thus far we’ve only examined two sets of data points: popularity at release (Billboard) and popularity today (Spotify).

Yet, we don’t know what happened in-between: a song’s trajectory from peak popularity until today. If we had such data points, we’d be able to understand how major cultural events or changes in taste influenced the trajectory of a song.

With Spotify, we have so much more detail: daily playcounts. We can understand a track's decay rate from its peak popularity: whether it’s quickly fading from culture or holding steady to be played by future generations.

Let’s look at the trajectory of the most popular tracks from 2013 and how they're faring today, in 2015.

If we were to review “Best of 2013” lists, Daft Punk’s Get Lucky and Robin Thicke’s Blurred Lines would be the cultural touchstones. Get Lucky won the Grammy for Record of the Year and Blurred Lines was nominated.

If my children's children were to ask what we listened to in 2013, I'd pick either of Pharrell’s collaborations or someone like Calvin Harris.

But that was two years ago, and we expect popularity to fade. Today, one track in particular has the most interesting trajectory: OneRepublic’s Counting Stars. Counting Stars never had breakout success following its release, yet it has managed to stay in the cultural zeitgeist for more than a year after its peak popularity.

One hypothesis: Counting Stars had a chance to spread organically via word-of-mouth since its April 2013 release, cascading from indie music circles to casual listeners. Get Lucky, on the other hand, dominated music channels in its heyday. Most people likely heard the track via mass media rather than friends.

When a track experiences such a rapid ascent, it’s a deal with the devil: the song achieves commercial success, but it also saturated culture in such a way that there’s immense listening fatigue among fans and fad-like connotations.

Lana Del Ray’s Young and Beautiful and Arctic Monkey’s Do I Wanna Know look like modern equivalents of At Last: little commercial success on its release, but steady growth over time. Today in 2015, both tracks are at parity with Royals and Get Lucky, and you’d probably never guess it.

What's still popular from different periods in history is almost never the obvious choice. Accolades, Grammys, and cultural dominance mean nothing to future generations.

The artists who have cult-followings and underground appeal: it’s a signal for some undefined musical quality that’s impossible for a hit song to replicate. Perhaps it means that they are culturally ahead of their time. Or perhaps generations will feel obligated to share it, for fear of it fading.

Either way, time will tell.