Why integrate a calendar in your online community? I highly recommend that publishers, especially those that serve a geographically local area, add an events list or calendar to their site. In addition to giving users yet another reason to return to your site, Calendar Hub lays out the user benefits quite clearly:

Stay Organized – reminders and deadlines for social, business and special events, including editorial & advertising closing dates.

Coordinate Your Team – to-do lists, tasks, milestones and to see what everyone else is doing and coordinate better.

Promote Yourself – special offers, limited-time sales & discounts and announcements, from groups & businesses.

Inform Your Audience – school dates, federal & commemorative holidays, meetings, festivals and more!

Stay in Touch – RSS, iCal and vCard standards can help you get reminders or import events into your own, private calendar , cel or iPhone.

There are many choices to add a calendar to your site – too many in fact – but I do have some requirements for any calendar that is to be integrated into a community before selecting among the many available options.

Any calendar must be affordable, flexible, easy-to-use, unbranded (preferably open-source or white-label) and user-friendly (preferably, with user submissions) plus allow for automated review/approval functions by the publisher. Not really a lot to ask, but most of these characteristics are – and I cannot emphasize this enough – vital if you want to maintain your sanity productivity.

Software – requires separate databse and/or site integration

jCal Pro – aka “the Joomla calendar” because, well, it integrates with Joomla *
EventList - supports multiple venues, categories, and details; especially useful for networking & affinity-based communities with diverse groups and genres *
http://www.planscalendar.com *
Jevents – an up-and-coming Joomla calendaring system
Thyme (Out of business May 2009) *
Localendar *
Webcal NG
Webcalendar
Vcalendar

Web-based - SaaS or outsourced solutions

EventsLink Network
Cozi
http://www.helioscalendar.com *
http://www.instantcal.com
famundo.com *
Jotlet *
Calendar Wiz
Connect Daily
30boxes
Matchbox
Trumba *(…ouch! $99.95 per month!?!)
HuntCal

The links marked with an asterisk are my favorites and recommendations – keep your eyes on Famundo and Jotlet in particular. Of course, you can search Google for “calendar” and you’ll find many commercial options, with many different prices – but not much more in the way of quality or functionality. (Believe me. Save your time. I looked.)