Considering the problems Twitter had in its earlier days just trying the basics performing well (which is a very hard problem, so not making a dig here) I'd ima

Considering the problems Twitter had in its earlier days just trying the basics performing well (which is a very hard problem, so not making a dig here) I'd imagine live hashtag filters for everyone would really slow down the service. It seems too much of a no-brainer feature to have so there has to be a technical reason why they haven't.