"You can put on your website/blog our widget and visitors will be able to send a voice message to you. People love talk, not type on keyboard. "
1) People browsing the internet already love to type on the keyboard. I don't see any shortage of text comments / messages. People writing their comments is the main staple of blogs, or Facebook and of Twitter.
2) Regarding the above, consider that blogs are textual in the first place, i.e the customer is there reading, not listening to someone. So why would he respond with voice?
3) People don't like leaving voice messages to people they don't know and expose their voice etc.
4) "Very easy" it is not. The huge masses without a Mac, don't usually have a built-in microphone on their computer. They would have to connect one to leave a message (and/or check their audio settings).
5) Has any "website/blog widget" ever gained any success in the market? With the possible exception of Disqus, and that is IF they make any money yet. I'm not sure "widgets" are a good business idea in the first place.
6) People also cannot leave a voice message while browsing a site from their work (which most people do most of their browsing from), because their boss/colleagues will hear them.
7) People might like talking in general, but that is to other people. Nobody likes leaving a message to an answering machine, which is what your service basically amounts to.