The Twitter website on mobile devices. I've just timed myself to see how long it took to view my own twitter profile on my phone (I don't use Twitter on my phone, hence I'm not logged in).

It took 15 seconds to load the profile, but I couldn't view any tweets until I'd pressed the "Not Now" button to the pop-up asking me to install the app. Five seconds later, I was able to view my most recent / pinned tweet.

This is all for a service that delivers a timeline of (primarily) text, with some images and video. It should not take 20 seconds to load!