Maybe you belong to a forum that discusses rodents. Or perhaps it's a website centered around flowers and plants and gardening. A classic hotrod discussion place? A website centered around all the red shirt actors who were devoured and or shot on alien planets during the original Star Trek series?

Whatever the online community, there are things you can do as an individual to make the experience of the whole group better. This is all about the opposite of being banned, the extreme other end of the spectrum. Follow these tips and you won't have to ever say they banned me.

Time

 It takes time to browse a site properly and flag spam posts and vote on content and participate in polls. If you spend time in an online community, though, you're doing your small part to make sure the community grows and becomes a useful place, fulfilling its destiny.
Time is a valuable thing, but if you invest into an online community with time, especially a good one, you're bound to get back even more than you put into it.

Knowledge

Knowledge is a precious thing. You might think that your specialized knowledge in some small focused area isn't of interest to many people, but by sharing your knowledge online with like minded people on a forum or another site, you can encourage others to do the same.

Great communities are started and grow when their members begin to dig deep in their reservoir of ideas and share them in a civilized manner with others who share the same interests. If you think about it most of what you know was probably taught to you by someone either directly or through a book or video or website. By giving back you can complete the cycle and make your favorite hangout online a great place for you and others.
Money

This might not apply to some of the larger online communities or forums that make a lot of money with advertising, but it could make all the difference to someone running a small niche website on a topic you love - whether it's the Trees of the Orient or World War Two Vehicle Wheels.
Donating even a few bucks toward server costs can help keep a good, small island of a website going so that you can enjoy the community there for years to come. You'll want to save this method for the forums and communities you really love online (so you don't drain your bank account), but it's something you can do to help forums thrive.

You may not be able to offer all of these things to the community you belong to online, but even just giving one can go a long way to making the Internet a better place for all. If you've ever been banned or been close to being banned, giving back to your online community is one way to redeem yourself online and make yourself a part of the productive portion of the web.