[IAmNotAFix]

As someone who started playing without having any idea about the platform landscape, and therefore chose the first Google result, which seemed to have a legit UI and domain name, and then met people who also happen to be on this platform, I would guess that their main strengths are: SEO, UI, brand, and the network effect.

[BbzzbB]

How much does network effect really matter past a certain point for low-to-mid ELO chess players? Whether there are 100 or 10k players in my ELO range at any given time, I'm unlikely to even notice it. IMO you just have to get past a certain threshold (which both Lichens and Chesscom have long passed); granted it is probably higher the better of a player you are as your opponent pool thins out.

[naet]

In my anecdotal experience, lichess has a smaller playerbase and it's most noticeable in the middle elo where certain lines or trends end up very popular in the lichess community and get overplayed. Whereas on chess.com I am more likely to see a bigger variety of openings. I had written off chess.com in favor of lichess but now that I play both I actually enjoy the chess.com user base as a differentiator between the two.