Except that the good stuff, you bought and continued to play, it continued to get played on the (not-oldies) radio, and in other public venues, and sometimes got revived in movies or tv shows. And usually had themes that were more universal (love) rather that more topical (streaking).
So one of the aspects that make a song “the Seventies-est” would be that it mostly faded away and most of your memories of it are strongly associated with that era and what was happening to you then.
You realize, of course, I was responding to Stephe96’s post above?
The Cover Of The Rolling Stone - Dr Hook & the Medicine Show
That Lady, by the Isley Brothers:
Brand New Key, by Melanie. Saccharine and chock-full of sexual innuendo - the Seventies in a nutshell.
And a gimmick song at that!
I’m always amused when I can tell people that song is about sex. It’s always a shock
It is sorta a gimmick song…given its contrast with Melanies other outstanding work.
But relative to real 70’s gimmick songs*…its not
Interesting given Steely Dans Sui Generis nature.
But for 70’s evoking Steely Dan numbers I’d go with ‘Rikki Don’t Lose That Number’.
All this, and no mention of Three Dog Night? Joy to the World, Brickyard Blues, Mama Told Me Not To Come, Shambala, and the like are probably at the tops of my musical memories of the 70s. Granted they formed in '67, and One was from '69 (or '68?)
Pnia Colada song, hands down.
Lyrics, mood (mindless and self absorbed), synthesizer (any real instruments at all played on this song?)
Not really “sung”, more rhythmically spoken.
Horrid.
Woah, you know people who are more dense than myself?!?!
Because I’m so oblivious that my wife simply knows that I’m not catching the subtext in a lot of conversations, but I got what that song was about on the first listen - maybe by the end of the first chorus.
Man, this would be a lot easier if we coild do 80’s songs. Because there can be only two: Haddaway’s song “What is Love?” that repeats “Lady don’t hurt me” over and over again, and that song that goes, “Oh yeah…” which I just learned is called “Oh Yeah”, by a band called Yellow.
Between those two songs, you pretty much have the 80’s covered. But the 70’s were much more diverse with everything from heavy metal to disco to singer-songwriter treacle.
And just in case you haven’t got that ‘Oh Yeah’ song out of your head after 33 years…
Why would I want it out of my head? 
Because it leaves no room for rational thought.
Oh nonsense, it totally leaves the language and logic centers mfuguguuwhrz staircase dinosaur winvnenen.
Yes, probably the most 80s song.
What is Love is probably the most 90’s song of all time - along with The Sign by Ace of Base or "Rhythm is a Dancer’ by Snap!
To provide relevant content, I’ll say this is really the right answer. As much as I love “Funkytown”, this one is kind of drenched in the middle ground of everything 70s. Heavy production? Check. Heavy Moog use? Check. Crazy vocal arrangements? Oh yes, check. Gloriously heavy use of solid state distortion? Oh my, yes, check. Plus, pretty sweet bass fills.
On top of that, when my co-workers in the mid 2000s were wondering things like “Hey, what’s the name of the song where they sing ‘Woman with the sweet lovin’ better than a white line!'?” They knew Google would flounder on that question, and knew I probably had the low-brow info stored in my head, and would just ask me. Yeah, I could name the artist, title and record with little pause. They had asked me about many different songs, but that question felt so very Seventies, even more than answering questions about ZZ Top.
An active link for the current day:
The 70s had:
Disco
Country crossover
Funk
Folk
Gimmick songs
Instrumentals
Movie and TV theme songs
Proto punk/new wave
The 70’s also had:
Hard Rock (Alice Cooper, Aerosmith)
Soft Rock (Eagles, Bob Seger, Wings)
Folk Rock (Paul Simon, James Taylor, John Prine)
Country Rock (Little Feat, Poco, Lynyrd Skynyrd)
Blues Rock ( ZZ Top, Stevie Ray Vaughan)
Acid Rock (Black Sabbath, Deep Purple)
Art Rock (Queen, Pink Floyd, David Bowie)
Prog Rock (Rush, Yes, King Crimson)
Big horn bands (Tijuana Brass, Tower of Power, Chicago)
Metal (Judas Priest, Motorhead)
Funk (Rick James, Stevie Wonder)
Reggae (Bob Marley, Jimmy Cliff)
Punk (Sex Pistols, The Clash)
New Wave (Blondie, Devo)
Outlaw Rock/Country (Waylon Jennings, Johnny Cash)
Artists that defied classification (Frank Zappa, Warren Zevon, Dylan, etc)
Plus the Disco, etc.
All of those artists were popular, mainstream radio hit artists, not just obscure genre artists no one has heard of. Many of them crossed genres. Eagles did everything from hard rock (Life in the Fast Lane) to straight up country. So did Skynyrd.
The 70’s get stereotyped as the ‘Disco era’, and we all remember the novelty songs, but actually it was one of the most experimental, widely varied decades for music we ever had.