Caching Bitly Links
Since Bitly links never change or expire, we recommend that publishers shorten long URLs on their back ends and cache the corresponding Bitly short URLs for repeated use. When the short URL for a given page is stored locally, it can easily be shared using a number of cut-and-paste buttons and widgets.
Note that the JavaScript wrapper for the Tweet Button — and any similar solution that calls the Bitly API on page load — is only recommended for smaller publishers, as larger publishers may encounter rate limiting issues. For more information on using the Bitly API to shorten links on your site, visit http://dev.Bitly.com.
Link Wrapping on Twitter
Twitter’s link wrapper t.co is designed to invisibly wrap all links across all Twitter clients, while still displaying the exact URL that you share. T.co wrapping does not affect Bitly’s analytics, and when t.co is working properly it should not impact your branding either. If you’re seeing t.co links in places where you aren’t expecting them, take a quick look at status.twitter.com or the @twitterAPI account on Twitter to see if there is a system-wide bug that is affecting the way that links are displayed on Twitter. If you are building your own tool or widget to display, for example, your company’s Twitter stream on your own website, be sure to follow the display guidelines provided by Twitter.