The first step is to determine if you actually have a problem.

You're assuming the 70% drop is a problem for IS. Maybe it is. Maybe it isn't.

What happens if they did lose 70% traffic but actually increased revenue and profits? Is it possible the buyers that stayed are buying Vetta and Agency which makes up for what was lost? They may have planned for, and expected, this drop.

Although theoretically possible, I think you would be hard pressed to find someone at iStock to stand up and say that this is a good trend and that it was planned (although they have said stranger things in the past).
IMO the trend during a recession would be for customers on average to trend away from more costly imagerie such as Vetta and Agency and look for suitable alternatives at better prices. At the end of the day when traffic to the site is down by 2/3, and most contributors are complaining about plummeting sales (especially large portfolio contributors which are more statistically significant) its generally not a good performance indicator.

+1 on that.  I have used the tax analogy before.  By taking more from us, they have decreased motivation and increased the strengths of their rivals.  The only way back for istock is a reversal of this policy but that's not likely, unless they are sold.  It could be a good opportunity for someone to buy them, now they are struggling but are they for sale?  It looks like istock is going to become a Getty collection and all the microstock images will be moved to Thinkstock. 

I think they have planned to reduce traffic, by increasing prices.  They have planned all these changes and they aren't for our benefit.  It looks like there's lots more on the way and I don't think most of us are going to benefit.  Perhaps they think that it will improve Getty, if the biggest microstock site has much less customers?  What I don't understand is that they seem to of forgotten about the other microstock sites.  Perhaps they underestimated the strength of the competition?  As long as they don't buy Shutterstock, their strategy seems flawed.

Since the iStock issues started, I did NOT experience a reduction in my overall earnings, but just a shift from iStock to all other sites, mainly Shutterstock. They may not care about us and microstock, but why should we keep on caring about them?
I just hope they will manage to keep their exclusives "happy" - that is, at least not too angry to leave - so they won't flood our independent marketplace (although I have some doubts that they are a real menace: standards at Shutterstock nowadays are higher than at iStock).

For the rest, they are slowly turning into a minor site - at least from the microstock perspective - so there's nothing to worry about. And since they have the worst upload method ever (barely acceptable thanks to DeepMeta), they are saving us a lot of time if they become completely irrelevant. Did anyone cry for months when Lucky Oliver (and similar) closed? No, because they meant nothing to most of us. That's what will happen in the near future if they don't change their attitude completely. A new owner is the only solution imo; otherwise, bye bye iStock. I'm not deleting port but just collecting what is left until they die, and I wish them good luck - sincerely - in their new adventures away from us and from microstock as we know it.

We must accept changes, in our own interest. Let's stop whining about a single site which used to be n.1 in the past, or we will look like those old photographers shouting at us microstockers instead of adapting. I spent the last few months uploading my entire port to all minor sites - including the virtually hopeless ones - and guess what? They completely replaced - and even surpassed - iStock loss collectively.

And the other site which is following them in the race to cut commissions is advised! Try not to reach the same point of no return, please.

No one knows but that metric isn`t measuring visits, its measuring unique visits. The people who visit forums are mostly contributors and they visit to check earnings, upload, keyword etc. so they don`t really affect the stats. In other words whether or not they visit the forums, they still only count for 1 visit so if they suddenly would all stop visiting forum, the stats would remain unaffected.

We should also take into consideration that their stats are based on 2,000,000 internet users (1%) in the US only.   They've already said they've ramped up their overseas marketing so perhaps European visitors have gone up?

I doubt it.  Since the European crisis heated up my sales during European business hours have gone way down.  Maybe it's just my port, but a most sales are coming from the US recently.