The experience acquired with silicon detectors at presently running high-intensity e+e- colliders is at the basis of the design of a new generation of trackers for Super-B Factories and Linear Collider. This new generation of machines will impose constraints which are more stringent with respect to the systems presently in operation. In this seminar I'll consider the Silicon Vertex Tracker of the BaBar experiment at SLAC as an example to discuss the main limitations of present detectors when extrapolated to the conditions of the new accelerators under design, in particular in terms of occupancy, radiation budget and material. I will show some of the solutions which are under evaluation and their impact on physics performance. I will also present some results of tests on APSEL_0 chip, the first prototype of a new CMOS monolithic active-pixel sensor developed by groups from Pisa and Pavia, which could be the hearth of the inner trackers in future detectors.