Now Stephen if you were around actually watching back then as it was happening you wouldn’t have to ask this very naive question as the answer is clearly and easily Rock/Mankind.
Here’s a good factual reporting from Rock316AE breakdown proving was the most popular feud from November 1998 - February 1999,:
But I’ll give a more through answer to your clearly well intended question with actual fact…
Austin/McMahon had been on the back burner since after the October 19th 1998 Raw, after Austin kidnapped McMahon with a gun and made him pee his pants and got the new WWF contract from Shane which he revealed the next week.
Austin/McMahon was put in the background behind the main feud of Rock/McMahon’s feud going into Survivor Series.
Then Austin/McMahon remained in the background hardly interacting, behind Austin/Undertaker & Rock/Mankind.
Austin/Undertaker was the main feud for Rock Bottom, leading to very low ppv buys at 290,000 buys.
Following the PPV they switched it up, Austin went on hiatus and became sporadic.
Yes people, despite WWE’s narratives, Austin was neither the main character nor even around much for the November - February of 1999 time period.
People who weren’t around watch a PPV like Wrestlemania 15 or St Valentines and think Austin was there every week, because they were not watching the show week to week.
Austin/McMahon was put on the back burner and they put Rock/Mankind as the main feud over Austin/McMahon going into 1999 and it led to the historic January 4th Rock/Mankind match.
Austin and McMahon hardly interacted during this period until the Royal Rumble, with Austin being a supplemental character to the Mankind vs Rock/Corporation feud, which was the main feud at the time, helping Mankind win the title.
Austin/McMahon was on the back burner to Rock/Mankind which dominated shows.
You’d know this if you were around back then, rather than merely watching WWE documentary highlights and looking on Wikipedia to see which match went last, rather than know what was going on the shows, because by that you’d think Triple H was a bigger star than Rock(see Royal Rumble & No Way Out 2000)
Further the most talked about match and reason for doing such great business for the Rumble PPV encore is the Rock/Mankind I quit match, it was covered in mainstream media… not Austin/McMahon.
It was also used as the main promotional feature for the Beyond The Mat documentary movie.
But as Austin would say, to put a Bottom Line on things, the WWF’s biggest promotional venture to sample the WWF to non wrestling fans was Halftime Heat, which was Sunday Night Heat’s special segment airing during the 1999 NFL Halftime.
And for this very important show, where they had to use their biggest stars, they chose Rock/Mankind, not Austin/McMahon.
And testament to this is the fact that they forced Mr. McMahon into being apart of it, using commentary as an excuse because they needed to get the biggest stars possible, yet Austin makes zero appearance for the WWF’s most important venture. If Austin/McMahon was indeed the biggest feud at the time, then that is what would have been highlighted for Halftime Heat.
We all know the story, Rock/Mankind did the highest viewership in cable history that night at the time breaking the record with a 6.6 rating and then Raw was able to translate from those casuals/non wrestling fans and start hitting 6, 7 and 8 ratings.
Austin/McMahon was no longer the most popular feud as it had been from April- October 1998, it was the secondary feud to Rock/Mankind from November-February 1999 and that’s concrete via ratings.
After October 1998 Austin/McMahon was no longer the most popular and main feud and either was in the background or shared importance with another feud until the Fully Loaded 1999 feud.
Let’s break this down factually so that it’s transparent:
Survivor Series 1998 - Rock/McMahon is the main feud over Austin McMahon, - is the secondary feud
December 1998 - Austin/McMahon is 3rd wheel story in the background to Austin/Taker and Rock/Mankind
Royal Rumble 1999 - Going into the PPV Rock/Mankind are getting the biggest ratings and Austin is hardly appearing, except for rare appearances, the build is behind Rock/Mankind and goes on last at PPV due to Rock interfering in it but still needing to win the title logically.
HalfTime Heat - Rock vs Mankind w/Mr. McMahon on commentary - Not only is Austin/McMahon secondary to Rock/Mankind, Austin has zero role in this very important venture, their biggest venture thus far.
St. Valentine’s Day massacre - With the exception of the delayed go home RAW, it’s secondary to Rock/Mankind and goes on last due to Big Show debut breaking hole in ring.
Wrestlemania 15 - Austin/McMahon is behind not only Rock/Austin storyline but also Rock and his frustration with the Corporation, only interaction is the beer bash also involving Rock & Shane, mostly geared towards The Rock.
This is a case where they watch the PPV where it ends with Austin having his feet over McMahon, and think that must’ve been the entire build… it wasn’t, they had more build up with St Valentines and even that was less in quantity than how much they interacted in 1998.
McMahon turns face, then turns back heel in June.
King of the Ring 1999 - Rock/Taker and Austin/McMahon main event feuds, with Rock/Taker getting the bigger ratings even against Austin/CEO storyline.
Fully Loaded 1999 - The Grand Finale to Austin/McMahon rivalry, the main feud, does only a shocking 370k buys.
So to answer the question…
From November 1998-February 1999, the most popular feud was Rock vs Mankind with Austin vs McMahon talking to 2nd place.
Austin/McMahon was indeed the most popularly rivalry in the WWF in 1998… Until Rock/Mankind.
Austin/McMahon was not more popular than Rock/Mankind and that’s substantiated by numbers/ratings.
Austin/McMahon was the most popular rivalry in the WWF from April 1998- October 1998, but then was secondary to Rock/Mankind from November 1998-February 1999.
It wouldn’t be the top popular feud again until the finale going into Fully Loaded and that’s where the rivalry ends.
Going into 1999, The Rock was the hottest star in the entire wrestling business to that point that WCW started to throw everything at wall to counter his popularity such as the Fingerpoke of doom & the NW elite:
But seeing as Stephen was 5 in 1999 it’s clear why he needed to ask this question:
This is the type of false history that happens, when you have those such as Stephen who admittedly has to ask because he was not there to watch as it was happening, when people watch mere highlights and documentaries and parrot revised history & narratives.
By the very same rewatching of select show intros and highlights someone could argue that for example Triple H/Cactus Jack was the main rivalry and most popular feud going into Royal Rumble 2000 because that’s the only thing that appears in the intro…
When in reality and everyone who was around back then knows this, is that The Rock and the Royal Rumble were the main build, with Rock getting the biggest ratings and doing the main promotion for it on TRL and etc, which you couldn’t know if you only rewatched PPVS instead of actually witnessing what was going on.
The same revisionist history that has those people thinking Austin/Mcmahon was more popular than the actual most popular feud of early 1999 in Rock/Mankind, is the same revisionism that has them laughably claim the Austin/McMahon feuded ended at Wrestlemania 17, 2 years after it was over at Fully Loaded 1999.
Exposing that they neither have a clue what they’re talking about nor that Austin/McMahon already teamed up and started bantering as pals in late 1999… but shhh, that goes against WWE’s documentaries that claim people “never thought they’d see Austin/McMahon work together”.
The fact that most are uninformed about The Rock/Mankind rivalry, is crazy to me, that literally was the hottest feud of its time until Rock/Austin.
can tell you all about corporate Rock and the well written and critically acclaimed Rock/Mankind feud.