
Image displaying ability to detect phones numbers and make a call
from within Firefox browser (Image courtesy of Luca)

Image displaying ability to detect phones numbers and ability
to type phone numbers from within Firefox browser
(Image courtesy of Luca)
While Firefox extensions are pretty cool and I have several installed myself, what I have seen so far in terms of features and usability of all of these Firefox VoIP extensions leave a lot to be desired. Sure, there's the coolness factor, but would I use any of these over Skype? I don't think so. Also, while many Firefox VoIP extensions are SIP compliant, they can be tied to a specific VoIP service provider, thus you are stuck using their VoIP service plans. More proprietary games. :(
Fortunately, with AbbeyPhone at least, you can enter your own SIP credentials to a 3rd-party VoIP service provider or even a SIP-based IP-PBX, such as Asterisk. OpenWengo also allows you to add your own SIP proxy settings. The ability to use your own SIP credentials does at least make these VoIP extensions a little more useful. But I can think of much better converged VoIP applications than one that simply plugs into my browser. You can check out my perfect softphone article for more details.