For some time now, I've happily been using bitly with a custom domain to shorten URLs on Twitter, but recently Twitter has decided to start shortening my already shortened URLs.
Will this affect my statistics on bitly?
Checking on the stats confirmed that the referrer was t.co.
*I believe, the reason there are couple of twitter.com & hootsuite.com referrers comes down to the way clients handle the API - twitter API provides both the t.co & the "long" URL(in this case, the shortened URL). If the client shows & sends request directly to the long URL, the obviously, the referrer won't be altered. However, twitter webpage shows the long URL but is actually linked to the short one and hence the referrer remains the short, i.e., t.co one.