1.7 was released last night but I pulled it as I was not happy with some of the functionality.
There are many improvements to performance and changes which should help make for better caching of user data. This'll reduce the load on your server as well as load-time of the map.
Full google api key support is now also enabled and should be used to avoid getting blacklisted by them (Not sure if they will black list, they certainly start denying requests if you get to chatty)
In a nutshell, the requirements for google are:
For the geo-encoding stuff:
Free up to 2,500 requests per day
$0.50 USD / 1,000 additional requests, up to 100,000 daily
See here:
https://developers.google.com/maps/pricing-and-plans/#details
At the moment the mass-update just chews through all the users so if you have more than 2500 users then it'll annoy them and you'll get DENIED results from the encoding attempt.
With 1.7 you can specify you key and increase that to many.
As for the map being viewed on your site -
Free until exceeding 25,000 map loads per day for 90 consecutive days
So, if you have 25k views of the map a day for 90 days then you'll need to purchase a key. It'll take me a while before I get to that point