There are many cool VoIP services today on the market providing residential phone line as well as long distance calling. I’ve noticed one group of sites which seem to be related:
What I like in their service — they have great rates for overseas calls, some are even so called free - you pay fixed fee and talk unlimited time (or close to that). Originally that was a PC-to-PHONE and PC-to-PC calls with their own client application required to be installed (like Skype). Plus they provided Call-In phone numbers for some cities (very short list).
What I do not like — their customer service sucks indeed, plus they do not improve much since the launch.
Recently they introduced a very nice feature: PHONE-to-PHONE calls initiated from their website, no headset required, no client application. Just enter two phone numbers whatever they are and it will connect them!
Many companies try to use Skype for their conference calls or even for technical support service (to save some money on expensive long distance calls). That requires many things from a customer:
- Skype application installed on customer’s PC
- Headset connected to the PC
- OR, instead of the first two items just one Skype enabled phone.
- Customer must be a registred user of Skype
- Rather good and stable internet connection
Now, imagine: on company’s contacts webpage a visitor clicks on a link of a customer support phone number. A popup window is displayed and the user is prompted to enter his phone number. Once confirmed, that will post an HTML request to a voip service provider to connect both numbers. Company number should be kept on server side (in the company profile). That should prevent from spoofing and connecting any two numbers due to a vulnerability.
- Giving such an interface to web developers will provoke much wider utilization of voip service
- Calling rates usually lower than via Skype, some are just dramatically lower, close to nothing!
- No special equipment required for a customer
- No Skype or any other account creation required
- Just regular phone or cell phone is needed
- Because of simplicity and no charges for users, it can be more popular that Skype approach.
Main drawback of this idea is scum users: what if somebody enters any number, not even his own, say of his prof? The prof won’t be happy with a web hosting company calling him again and again. 
Only because one of his students is having fun after 2 gallons of beer. 
But, similar tricks are possible with any voip-out service, like Skype-Out: you call from your Skype to any land line number without being identified… I think this problem is solvable. For example, when system calls in, a recorded message should prompt an answered party to confirm the call by pressing certain digits or by even entering a code given at the website page. If no code entered, then a call is ended with recorded excuses and not customer support rep. is bothered! Something like that… (Of course, all calls, even failed, must be paid by voip service account owner i.e. by the company).
Does something like that exists already?! Never seen…