You do not need to create multiple emails to create multiple accounts.
Yesterday, I created a survey that collects Twitter usage data from Twitter users. Just from the initial first few hours of data, I can already see that most users have more than 1 Twitter account and there certainly exist users who have more than 5.
Saku told me that she has 15 Twitter accounts and I asked her if it was a pain creating a new email for each of those accounts and she told me a trick that was taught to her by my former roommate.
You can use firstname.lastname@example.org to create new accounts on Twitter, or any other site, and all its mail will redirect back to the original email@example.com.
If I made a Twitter account with each of these, they’ll all redirect its mail back to the main one.
I hope this was helpful. I was completely mind-blown myself.