The "signup friction" argument's a straw men; no sane startup seeks to add friction to the signup process. the bogus (implied) assertion in the comment is that requiring a Twitter account to use a new web app in beta is overly restrictive / cumbersome.

The only way that would make sense is if beta testers don't have Twitter accounts, since OAuthing with an existing account reduces friction. Twitter's been around for four years and seems fairly well established among early adopters like HN readers, so counting on a critical mass of beta testers to have Twitter accounts hardly seems a stretch, even if those users aren't very active tweeters.

i for one was very glad not to need to enter an email address, pick a login name, etc; the oauth process handled that for me. ymmv