Hi,
First of all, I wanted to thank you for developing such a wonderful plugin! It works & works straight out of the box with minimal config. In fact to me, this plugin is almost PERFECT!
I say "almost". I do so because what I have noticed is that as soon as I click on the "XML-Sitemap" link under Settings menu (in Admin panel), the XML sitemap is generated. So which means, this process runs each time I visit this link. I have to be very careful to see that I do not click on that link, which is quite a bit of trouble when I am in a rush & I accidentally click on the link. I don't want our blog to labelled as spam due to the excessive pinging that can result out of such auto-generations. Unless I have missed, I didn't notice any options to work around this issue.
To solve this issue, I have an idea. Instead of generating the sitemap automatically whenever the link is visited, how about providing a big button that says: "Generate XML-Sitemap Now" on the page & have the user click this button to generate the XML Sitemap?
I know there could be other users who are used to the existing way. To honor such users, I have additional idea. Maybe you can create a radio option in settings that lets you select whether the user wants the XML sitemap to be generated automatically whenever the page is visited or when the button is clicked? That way, you would have covered the needs of both kind of users.
I hope my requirement/input helps you in making your product even more better. Once again, thank you for all your hard work, time & efforts that you have spent in developing such a splendid plugin!
http://wordpress.org/extend/plugins/google-sitemap-generator/