Mine is actually Scryfall. I think I just googled for good deckbuilders and saw the stats on this site were easily readable and intuitive. I still don't quite get the editor or stats on Tappedout. To me it's really confusing so I will continue using Deckstats. Also found a nice little community here - <3.
I think, yes, the activity has risen for sure. I've been here almost 7 years, and it's my favourte deckbuilding site. It has the best and most well-structured foundation than TappedOut and MTGGoldfish. Contrary to MustaKotka? I don't get on TappedOut the same kind of appreciation as I do here, but both are fantastic deckbuilding sites, albeit DeckStats for me is the best.
Regards,
Chavdar