Post with their general FAQ on the change. (copied below)
Subscription free Global Agenda FAQWhy did you decide to make this change?After receiving feedback from many existing and potential players, we believe that we will have the most thriving community by offering a non-subscription purchase model.
If I purchased the game, will I be charged for anything I’m currently playing?No, there are no additional charges for the current content, including the Agency-vs-Agency gameplay and all currently available PvE modes. In the future, players may elect to purchase new expansions with additional content.
How much will expansion cost in the future?We expect new expansions will be priced competitively when compared to expansions of other non-subscription games.
How often are expansions going to be released?Expansions are expected to be released once or twice per year.
When is the next expansion expected to be released?We currently anticipate that the next expansion will be released about 6 months from now (end 2010). The content within the Sandstorm expansion this Summer will be included in the initial game purchase price.
What will expansions include?Expansions will include new content, usually centered around a new world region, with new maps, new weapons/devices, new PvE encounters, new achievements, new social areas, new open zones and new crafting.
What happens if an expansion raises the level cap?All players will be able to continue to level their characters to the maximum level cap regardless of purchasing an expansion.
Is there a cost for patches between expansions?There is no cost for updates between expansions.
Can I skip expansions or do I have to buy each of them in order?You can skip expansions, although you will not be able to gain access to the content that the particular expansion provided until it’s purchased.
Will my game still work if I don't buy expansions?Yes, you will still be able to play with other players and have access to all the content in the original purchase.
Are free trials going to change with this plan?There are no changes to free trial at this time.
What happens to pre-subscribers?Pre-subscribers will not be charged any subscription fees, but will keep all the extra bonuses received for the pre-subscription. Pre-subscribers can leave their payment information for future purchases. (Note: The daily token awards for pre-subscribers will end on June 25).
Is this plan for all countries/regions?This new pricing plan is the same for all regions.
Are there other games using this kind of purchase model?Guild Wars would be considered to have a very similar purchase model.
Are all of the current planned features for 1.3 (Sandstorm expansion) included in the current purchase?All existing 1.3 features that are currently in the game are included. The first Open Zone will also be included (once released later this summer), in addition to Defense missions and Tournaments. 64-player War Zones are planned for a future expansion.
Is there going to be a cost to playing Agency-vs-Agency (AvA)?No, all current AvA game-play is included in the single-purchase price. Once an expansion is available, it may be required to continue playing AvA to ensure that everyone is playing on the same maps.
What is the future of AvA in this model?AvA will continue to be one of the game play modes available to all players.
Is there going to be an additional cost for playing the current high level Solo or Team Special-Ops missions?No, all current content at all difficulty levels is included as part of the one-time game purchase.
If I don't have an expansion, does that mean I can't play with my friends?You can still play with your friends on any content that each of you have purchased.
Will players with expansions be more powerful than I am?Expansions will offer some new weapons/devices to give the player additional play styles for more variety. These will be designed to be different and not strictly ‘better’. However due to balancing, some may end up being a bit weaker or stronger.