Is FA becoming a paying service? I noticed this today when looking up a flight.
No, just offering a pay service. Looks to be providing flight history, that’s about it.
It’s listed above every aircraft’s/flight number’s activity logs. Offers access to history back to June 2005.
As you discovered, we’ve added another commercial service offering flight histories back to June 2005 in response to customer demand.
The current 4 month flight history in the Activity Log will remain free.
It’s only a matter of time folks… 
No, I think it’s just an enhancement for those few who complain that there’s only a few months’ worth of history on the free site.
Wrong again. If you would have taken less than two minutes of your time to search the FA forum you would have found THIS thread.
The free FlightAware website has always been and will always be free and we have no intention of ever reducing the services or data we make available to our registered users. As others have remarked, FlightAware exists in large part because its founders considered it unreasonable to have to pay for live flight tracking.
That said, we have also always offered commercial data services that go beyond what is available for free on the FlightAware.com website. Among these services is long-horizon flight histories which we’ve been selling to customers who call or write and ask.
Recent significant expansion of our server resources has made it practical for us to offer these flight history reports in an automated fashion. This is the reason the link to these reports has appeared on the website. We’re now able to offer these history reports cheaper (since it takes less human labor to produce them) and more conveniently (since the website is available even on holidays and weekends) to our customers. It’s a win for everyone.
Rest assured that the free web site services are in no way jeopardized by this additional feature.
Alright now I can sleep well tonight!