Klaroline is bigger but Olicity is much more active and growing.
KC has a very BIG fanbase than even Olicity cannot go up against with ease especially considering that the KC fandom can trend on short notice (the Olicity fandom is getting very good at that too) and can put up a hell of fight in the polls like no other ship when there have been no scenes and even no hope for many for a very long time now. And this is the basic difference. The KC fandom has been disrespected and abused by the writers and in their interactive relations and through the narrative of both shows while Klaroline has has “closure” and no scenes and yet the fandom still holds great power. While Olicity has been growing inside the narrative and the writers took care of it and were always very welcoming to the fandom with their PR. Especially lately.
You see it is an unfair comparison when people are trying to compare ships that are active with ships that are put on ice and yet the Klaroline fanbase even in that state is still fighting and is still a fan magnet like no other.
Check out the fanfiction for example. Klaroline has in ffnet 5.400 stories and the Klaroline story has been in the screens for 2 years plus 1 year with only one crossover. The Arrow fandom in ffnet has 3.000 stories all together for their 2 years that are on air in which 2.200 are Olicity ones. Now that Olicity is going to have more intimate scenes and a whole plot revolving them as a romantic ship I expect their fanfic number to increase a lot but even like that you can see how Klaroline is influencing people’s inspiration and how inside the Arrow fandom Olicity does too.
Klaroline is more recognized in the media than Olicity. But Olicity is gaining a lot of attention too. Klaroline has also gained the critic’s attention something that not many ships can do.
The Olicity fandom however is constantly growing and is more active. Especially now. If Klaroline was active though there would be no comparison. Remember when Klaroline was active? The fandom could compete even with much larger fanbases from much larger networks (one this is for certain, if Klaroline was in the hands of the Arrow producers the fandom and the ship would have been handled with respect and they would have treated it like a goldmine. The same way they are doing with Olicity now)
Olicity has had much more scenes than Klaroline and their flow inside the narrative and their development was better handled inside the writing. It was step by step. It was there all the time. They have been a constant in almost every episode, either it was a reference, a small scene or a full load of Olicity scenes. Klaroline even when it was on TVD was happening pretty much on and for the sweeps and people had even to wait for months until they would get a new scene. Which is not the case with Olicity (thank God!).
Plus Olicity has many Klaroline fans supporting too and after Klaroline was put on ice many KC fans turned their attention to Olicity as a result.
It is a close call these days tbh. Olicity is a fandom that is very united, organized and it keeps growing. It is REALLY active and a fun place to be. Felicity Smoak and Olicity have made an impact on the media. It is something that always comes up at interviews and panels and trends and questions. It has caused an uproar and inside the Arrow fandom is basically the largest ship. It is one of the most positive and successful ships of CW right now also.
In the end it makes no difference which fandom is larger and which one is a little smaller. Both ships are ships that people embraced. Both ships have BIG fandoms. Both ships created a buzz in the media and are giving people a lot of feeling and inspiration and a good time. And that is what matters.