Google’s uses a bunch of things to decide what pages are most relevant whenever you search, one of the most important being links. It relies heavily on things like number of links pointing to you, age of links, the anchor text of links, and a bunch of details in between.
On Twitter the rules are different. It’s all moving rather than static. Something that’s been around for longer might not be as relevant as something newer.
And you decide what’s important by who you follow. Followers and numbers matter in different a way than a regular link. If Fast Company says something about a marketing conference it’s probably more relevant than if I do. But if I say something about a marketing conference happening in Halifax then it’s different. Especially if other people around me are too. So that might be of interest, but not to everyone, not to the masses.
