To call voice over IP a threat to basic phone service revenue would seem to be a statement of the obvious. But to this point, I was firmly convinced that only the cable companies were likely to exploit VoIP in any way that would seriously damage traditional phone service.

At last week's VON '05 in Boston, there were much stronger indications that VoIP has a larger appeal--and no, it has nothing to do with eBay or Google.

Both AOL and EarthLink announced stronger forays into voice service, making it clear that this represents a clear growth opportunity for them. They are partnering with other networks--Level 3 Communications and Covad Communications, for example--and looking to leverage existing brand names and customer relationships. In EarthLink's case, that means its stellar reputation for customer support and service as an ISP and in AOL's case, that's 140 million AOL Instant Messaging users.

While AOL got the bigger splash and may initially draw the most attention and the largest group of curious customers, EarthLink may well represent the prototypical independent VoIP provider that truly gains market traction. This is a company that survived as an ISP when most of its former competitors are gone, acquired or seriously diminished. EarthLink regularly wins awards for its customer service, and is promising to uphold that reputation.

Just as importantly, it is working with partners who are ready to support the rollout of key technologies--ADSL 2+ in the case of Covad and dual mode Wi-Fi/CDMA in the case of SK Telecom of Korea--that will give its VoIP offerings greater appeal.

There are still dozens if not hundreds of VoIP providers who will continue to grow their base, but I'm keeping an eye on these two, and particularly on EarthLink.

E-mail me at cwilson3@primediabusiness.com.