tips are supposed to go to tips@techcrunch.com but when I was there it was a total firehose you had to filter out into a folder and wade through all at once. You'd probably be okay emailing a writer directly if you have a good reason to think they rather than someone else should be receiving your pitch.
Word. I'll note for others that impressing a journo involves not looking up their most recent clips and figuring our how your topic is like those too, but rather understanding the needs of that particular writer in their particular beat and trying to add value for her while extracting some value of your own as well.
