Most of my Twitter usage is through mobile (as I suspect is the case for many). So excuse me if this is old news When you follow someone on Twitter, it immediately expands to reveal others "you might also want to follow". It is directly in-line, relevant and surely drives deeper usage / engagement. It makes sense both for the person following and the person tweeting (another avenue to drive attention & grow the following). It could also be another avenue to help onboard / better engage big brands. Earlier I wrote a post about ESPN's Twitter usage (My Response to Mark Cuban’s: Does ESPN.com Have a Twitter Problem?) - this seems like a big lever for ESPN, ESPN fans and consequently Twitter.
Upon following an ESPN personality / handle (either as defined by Twitter's search algorithm or a verified account), it could prompt some sort of walk-through that better connects other ESPN personalities. Right now it is very difficult to follow the right people - and that's partially ESPN's fault and partially Twitter's.
Users wouldn't find it intrusive - and in fact, they would probably appreciate it. Brands would absolutely appreciate the chance to promote related handles (right now they create background graphics to do so). And Twitter would get more deeply engaged users, with bigger follow lists and more engaged brands (with greater followings).
In fact, the brands would likely pay on a per-action / promotion basis. For instance, as Polaris Ventures, we have several people with Twitter accounts, a master account and a Dogpatch Labs account. I'd gladly work to better connect those - and if that came at a reasonable fee, I'd gladly sign up.
For a bigger brand like ESPN, it's clearly for more powerful and therefor more valuable....