Go to Your Stuff > Preferences. On the Your Preferences page, you'll be able to set your locale and time zone. You can also set whether a discussion thread and its replies should be displayed all on one level (flat) or indented hierarchically (threaded).
You might want to ensure you have the right locale chosen here if you intend to use Jive SBS from web browsers set to another locale -- such as in an Internet cafe in another country, for example. Your preference here takes precedence. By the same token, if you want to make sure you use the locale set by an administrator for the entire community, make sure that your web browser doesn't have a locale set (or else the browser locale will override the community setting).
In the email notifications preferences you can set whether you should automatically get an email when you create or comment on content.
You can choose to regularly receive a summary that briefly lists community activity you might care about. This includes activity related to your content, your connections, and popular items in the community. You can set when the summary is sent to you -- daily, semi-weekly (Tuesday and Friday), weekly (Thursday), or never. By default, the summary is sent at 9 a.m. on the days you specify here.