All the word on the street was that IF Atlanta returned to pro soccer, it would not be via the Silverbacks. The last few years of the pro team were not successful financially and things didn't look viable in the future. Rumors were that other investors would be necessary to make it happen.
Two years have passed since the Silverbacks took the field. USL-D1 has imploded and now we have the NASL. Same idea of a national 2nd division with the same type of costs...
Rumors in Minnesota have Traffic (owners of Miami FC and doing big business in Central & South America) providing funding for that club to return. Pure speculation here, but could Traffic be funding Atlanta as well in order to provide a league for its many players to gain experience in? From a player development and sales standpoint, it could make sense for Traffic to essentially control the market.
I'm sure this will be updated as events unfold. Be on the lookout for more about the return of pro soccer to Atlanta.
UPDATE: For what it's worth, the official site hasn't been updated yet beyond the NASL announcement at the beginning of 2010.