We live in time, whether we realise it or not. Time is ultimately the product of entropy. The universe is a closed system travelling from perfect order to perfect disorder. The unevenness of the universe at its earliest known moments is what produced history, we have galaxies, stars, planets and people. The Earth itself is an open system so, within this small context, we experience counter-tendencies, such as the origin of species or the rise of human civilisation.
The experience of time is relative, either to entropy or counter-entropy. In the case of humanity it seems scientists are homing in on a theory of time based on the repetition of actions against the activity of oscillator cells in the brain. A well-developed mind is actually very good at estimating time, at least in certain contexts say catching a ball, playing a piece of music, driving a car and so on.
The idea that time is relative is less interesting than the suggestion that the estimation of time is based upon practical activity: the role of labour in the development of time. Although it must be said there is a conflict between the relative nature of time and the capitalist prerogative to homogenise and quantify time. The meaning of time changes through different epochs, changes with the application of new technology. Perhaps mostly importantly the perception of time is different for different classes; different classes are different sets of relationships within the world of work.
Generally speaking instant communication has decentralised work. Some (not exhaustive) observations:
1) The difficulty of commuting between home and work has led to the rise of flexitime. This combined with mobile communication has eroded the traditional sense of time.
2) The laptop allows much white-collar work to be done on the move.
3) Manufacturing, especially high-end manufacturing, often takes place in (spatially) long chains. Firms save money by improving freight and communication at the expense of stockpiling, in other words by using just in time delivery.
4) This does not overcome the labour/capital antagonism, it just reorganises it. While under late capitalism whole swathes of our society are no longer dominated by large factories (the traditionally recognised concentrations of workers), this means, from our point of view, different and sometimes new sections of the working class have sectional strength. In this case communication, freight, IT and so on. Small sections of workers in the chain of production can also have an impact, as can workers in primary input industries.