One of the earliest requests for features on OpenCorporates was actually from company owners – the ability to add data about their company, especially websites and telephone numbers.
Well, now at last you can do that, and not just company owners, but anyone who’s logged in. The requirement to log in is pretty important, as we’re almost obsessive about provenance on OpenCorporates. Put simply, anybody using OpenCorporates should be able to know where (and when) that information originated, whether from a company register, a data source such as the UK’s public spending data, or from an OpenCorporates user.
How do you do it? Just log in using the subtle ‘login’ link at the top right of the page. As well as allowing logging in using your Twitter account, you can also now log in using LinkedIn. The procedure’s the same – just click on the link, log in to your LinkedIn account, confirm that you’re happy to use LinkedIn to authenticate your OpenCorporates account, and you’re done. The whole thing should take no more than 30 seconds.
Then on the company page, just click on ‘Add Data About This Company’:
Add the data – in this case, we’re adding data about Trafigura BV, a Dutch company that’s part of the Trafigura group:
And that’s it. And of course, the information you’ve added is available to the community as data in a variety of ways under the same open licence as the rest of OpenCorporates.
blog.opencorporates.com 
Just added some user-generated content to this company http://opencorporates.com/companies/gb/01737985 and saw that I now have a list of contributions on my user page http://opencorporates.com/users/30 – Good work Chris. Perhaps you might like to explore some ‘badgification’ as on http://ideas.okfn.org/badges/ .
Good work. Yes, that’s on the way!
I would like to contribute to OpenCorporates, but I don’t use social networking sites. I have no interest in outsourcing my friendships to commercial corporations — or even to nonprofits. And I’m not interested in “tying” my work on OpenCorporates to my work on any other website (e.g. Wikipedia). I don’t think it’s a bonus when anyone can track what I’m doing in various places around the web. Please provide just a way to login to your site using an account unique to your site (or a way to contribute without logging in).
I understand your concerns, but I think there are two issues. The first is how to identify oneself, to allow others to understand whether the contribution has authority in some sense (or is a spammer). Admittedly that doesn’t have to be a Twitter or Linked In — it could be Identi.ca, or some other open open, or non-commercial service, and would welcome suggestions. The second is to have a sign in that is easy enough to allow users to sign in, but that doesn’t have lots of friction, such as captchas and the like. We’re not the only ones trying to get the balance right, and we’re open to suggestion, but it isn’t a trivial problem to solve.