Definitely not get email address, as people probably don't want their email addresses sharing. Some kind of built-in messaging system is a better idea, but that might require some work.
If you need to contact somebody, there is the PyWeek IRC, but it's only really active a few weeks before and during the competition. Another alternative is by putting a comment on a Diary Entry from them, that way they'll receive an email saying you commented on their post.
I don't really want to include a whole new messaging system within the site, but I agree that commenting on diary entries is an awful way to contact people.
Why do you want to contact them?
I don't really want to include a whole new messaging system within the site, but I agree that commenting on diary entries is an awful way to contact people.