Well yesterday was brutal, but I've had a look at my Analytics data and it's not all bad. If you've been hit then I don't recommend you do anything for a week or so, just to let the dust settle .
My AdSense income is down another 30-40%. The main thing to get hit is HubPages (again!). This was my 2nd best AdSense income source. My Hubs appear to have lost 90% of their Google traffic. Ouch! Let me know if you've seen similar.
My 3rd best site has been hit hard, with maybe an 80% loss of Google traffic.
One of my EMD sites has been hit, but the rest seem to be OK. I've definitely got sites that are unaffected, which is good news. When the dust settles, I'll focus on these.
Also my best site got thrown out of Google ages ago, but it still gets a stack of Yahoo/Bing traffic. Somebody needs to write a WSO about ranking good in these!
Worst affected are my oldest sites. These have been decimated. And to whoever says that you should switch from niche sites to real businesses, well my real business has been sunk!
I think the major signal for Google is once again LINK BUILDING. There's a clear pattern now with my niche sites - more link building has equaled a bigger hit. I haven't actually done much linking, and I've certainly never bought Fiverr gigs etc.
I don't think quality is an issue - my best quality niche site has been hit and I think this is because I put it in a Blog network. I'll take it out and see what happens.
It's the weekend so it's hard to tell if my B2B sites have been affected. I'm rebuilding one so I can't tell for that one.
One of my other sites has gone from the SERPs. I'm pretty sure that there's now a Google duplicate content penalty that kicks in if you move content from one site to another. My Hubs got b& so I tried moving them to other sites. I think this does work, but you need to unpublish them for 3 months or more, or just rewrite them.
Anyway, I'll be interested to hear what's happened to your HubPages, niche sites, authority sites etc. etc.