If they implemented cross-server groups as a free feature, they will, guaranteed, suffer lost sales from people who no longer wish to buy the realm transfer service. The overlap between the customers of the two features may be small, but it's not zero.

Try to convince your boss to let you spend the next few weeks working on something that can only produce a net loss for your company. See how well that works for you.

Being able to run Heroics and Dungeons with RealID friends cross-server is not the same as transferring realms, which gives you access to a new community, raiding guilds, and PvP guilds (not to mention an escape from your prior realm should you have a, ahem, reputation).

If this service allowed cross-realm grouping for raids and PvP without RealID I might agree that Realm Transfer fees would be diminished, but not given its current limitations.

Thats wrong smashbolt. you cant raid cross server. People don't transfer servers so they can do 5 mans.

"you cant raid cross server. People don't transfer servers so they can do 5 mans."

Following this train of thought, it could take some of the fear out of someone who was planning on doing a paid server transfer to join a raiding guild. Who wants to pay all that money to find out the guild actually sucks or that they don't think you're a good player? Now people can do trial runs in cross server heroics.

So, maybe it's actually more likely to increase server transfers than decrease them.

(I'm just playing devil's advocate. I'm not sure I think either scenario is likely.)

"Thats wrong smashbolt. you cant raid cross server. People don't transfer servers so they can do 5 mans."

I doubt that players who participate in top-end content (raids or rated PvP) are the only people who ever transfer servers. For some who are entrenched on a given server with lots of alts and tradeskills available, transferring and rerolling are not very attractive options when all you want to do is play WoW together sometimes with your sister-in-law or co-worker. Sure, you can't stare at each other's avatars in Orgrimmar or run daily quests together this way, but you can still do dungeons with those other people without entailing the high immediate cost (in time or money) of uprooting from your other server.

That said, Cutaia has a good point: this service does allow people to "try out" a guild by running heroics with them before forking over for a transfer... so ehh, I guess maybe it all comes out even in the end.