[kshay]

> It's not one thing that cause the drop but a combination of things

Let me propose a bold generalization based on observations of sites of all sizes wrestling with Google over the last 20 years, and to which there are certainly exceptions (this case may be one):

It’s always one thing.

Of course, there are always a multitude of improvements that can be made to nibble around the edges and get incremental improvements in various metrics. And a gradual change in traffic may have several simultaneous sources.

But when the effect is an identifiable precipitous drop in search traffic, almost all the time, it turns out there was a single reason, whether a change Google made or a change the site made.

This may be a totally unhelpful observation, and feel free to ignore it. But in these situations I’ve come to find it’s more fruitful to look for A Cause than to approach it as “a little here, a little there.”

[johnny_reilly]

I've listed all the causes I can think of. Does any strike you as "the one"?

[kshay]

Honestly, the thing about other sites using your GA tag seems like the biggest red flag/potential for some Google algorithm to have actively started penalizing you. The timing doesn’t quite track, but maybe some interaction between that and the spam update?