Instant Username Search - Check out if your username is available
Hacker News Stack - Focus on the really fresh and unread news in Hacker News.
Namechk - See if your username is available on 100+ social networks
Hacker News Front Page Explorer - A database of top ranking Hacker News front page posts
Handlescout - Get notified when a Twitter username becomes available
ParityDeals - ParityDeals automates dynamic pricing, enabling you to adjust prices based on location, time of day, or season and boost conversions in individual markets