On the one hand, as a player, I'm happy to see regulated online gaming proliferating in the USA. The addition of Pennsylvania will literally double the amount of US citizens with access to online poker. Should PA get their **** together and combine player pools with NJ, DE, and NV, then that could definitely spark more action in other states.
On the other hand, if PA has a **** poor implementation like other states have done upon launch (here's looking at you New Jersey), then they won't inspire much confidence. Remember how far off the mark New Jersey's estimates of gaming revenue were (and still are?).
As an affiliate in the offshore brands, this is bad news. Oh well, knew it was going to happen eventually. I still say we're well over a decade away from large scale adoption.