Thanks to itsthinkingstill, he's recorded some VOIP gameplay footage so you all can see how well it runs. A video tutorial on setting this all up is in the works! NetLink VOIP Rally/Daytona Gameplay - NetLink VOIP Virtual On/Bomberman Gameplay - NetLink Zone - Another example recorded recently - Guide for all this is at http://dreamcast-talk.com/forum/viewtopic.php?f=2&t=8453&p=90224#p90224
Jeff Nihleah (rush of Black Out! for the Jaguar) is one of the responsables for this so shoutout to him and his team
currently I know of 9 people so far and ive played with many of them. There could be more but these are just the people Im aware from dreamcast talk forums.
this number has grown quite a bit now (i think its around 12-15) so is a slowly growing fan base. The setting have also been improved so the games over time are getting smother. If you want the tutorial video he was talking about head here
Some more cool new behind this topic is that recently the Netlink Zone Leader boards and Guestbook are now back online for the first time since 2001!