You can just leave a fake one - oversight on my part; it shouldn't be required.

I tried "@faketwitter" as the twitter user name and it complained about it. I'm not too familiar with twitter user names but I thought that should work.

edit: removed the @ sign and it worked.

Yeah, I don't really use twitter either. Don't need another time vampire.

I see from the owner's comment on here that its not required, please update the site to reflect this. Maybe put a space for "other profile url" so I could perhaps link to my presence here for example.

Other service owners, please take note!

I looked at applying long ago, but the 'URL of something you've made' made me turn around and leave. I don't think it said anything about 'developers' at the time, though, just 'designers'. Oddly, I had a website that I designed (and that I used this time) but I didn't think to submit it.

Well you 'something you've made' can be something you've 'developed'. Some app you built? Screen shots of some projects or work you did?

Could be anything - github/bitbucket link to some OSS, site you designed/coded, etc.