Yes. Kronolith 2.0 introduced shared calendars. You can view as many calendars as you want in one overlaid view, and control access to each of your calendars on a per-user basis.
Preliminary syncing support is available in the bleeding-edge development releases. See http://horde.org/sync/.
If your system administrator has configured it, and you have set an email address in your Horde preferences, you will get an email when an alarm "goes off". You can pick inline, popup, or email reminders in options.
Yes. Kronolith 2.0 supports the iCalendar/vCalendar format for importing and exporting and sending iCalendar invitations for e-mail based scheduling. As such it is now interoperable with any calendar/email system which can either send or receive standard iCalendar attachments. This means that you can create a kronolith event, send invitations for that event to any email addresses desired, and the email recipients can then add the event to their calendars automatically.
A Free/Busy URL does just what it says: it provides information about whether something or someone is free or busy, via a URL. Generally, this will be in iCalendar format, with a VFREEBUSY component. Applications generate these in different ways and publish them in different ways. In Kronolith you can specify the number and which calendars are used to generate the data.
In Kronolith 2.0.x, you have to specify each calendar separately in the Free/Busy URL. So if you want to have two calendars, say one with public events, and one with private, and you want the combination of events on both of them to constitute your Free/Busy info, you have to specify both of them because the URLs are calendar based only. The URLs are of the form:
http://www.example.com/horde/kronolith/fb.php?c=kronolith_share http://www.example.com/horde/kronolith/fb.php?c[]=kronolith_share1&c[]=kronolith_share2
In Kronolith 2.1 or higher, there is a new preference available that lets you specify one or more calendars, whose entries are to be merged to generate your Free/Busy information. The above formats still work, for a per calendar share basis, but a new format is added of the form:
http://www.example.com/horde/kronolith/fb.php?u=username
Now how is this information useful? Well, if you're using applications that know how to use these URLs to check if you're free or busy, it can facilitate scheduling of meetings or events. So the idea is you publish a static URL (in much the same way that you give out an email address, a phone number, mailing address, etc.) and then people can use that to check if you're available. Important to note is that no information about what you have scheduled is available. It's just whether or not you are free or not.
To fully use this in Kronolith you need:
Now, when you create an event, check out the Attendees area. Type in one or more email addresses, and if they are in your address book, and if they have a Free/Busy URL, their availability will show up.
For others to use your URL, if they are on your system, they need to have you in their address book, or there needs to be a shared address book that contains these entries (we maintain and publish these as part of our organizational directory, for instance). If the users aren't on your system, just give them your URL and they can plug it into whatever they are using that takes advantage of it.