Since chatting in Achat is not topic-restricted, it makes no technical problems to propose your partner to meet in a real life.
Have anybody done that? Did it work out?
Now, as a general rule — Achat is a fun game, and it's fun because of your anonymosity. So, is it OK for you, if your partner suggests you a meeting in a real-life — say, over a cup of tea in a cafe? Would you consider such a proposal seriously, or would it make you irritated as an outing attempt, and possibly make you to add that person to your ignore list?
It could be implemented in a really straightforward way with the use of Skype Public API. The Public API allows you to use Skype features from a different software. It would look like, that an user of Achat would have to install Skype and register a Skype account; then he would type in his skype account name somewhere in his character settings; after that, whenever he would like to initiate a voice chat with other Achat user, the Achat would do the voice call with the use of Skype Public API.