iOS (Jailbroken): Some apps have a handy built-in browser that allows you to quickly load up links, but apps like Mail and Messages don't. To open a link, you have to switch over to Safari. BrowseInApp is a jailbreak tweak that adds a small browser to just about any app.
When you click on a link in an app with BrowseInApp enabled, you're given the option to load the link in Safari or in app. Tap "Open in app" and the link will load up right there. You don't have to wait for Safari to load. It's simple, but it ends up coming in handy when you just want to quickly peek at a website or file. BrowseInApp is 99¢ in the Big Boss Repository.