Perplexed by 3 approaches to twitter

At last Friday's CU Social Media Cafe, we discussed twitter. It soon became apparent that three experts adopted three completely different ways of managing their digital identity.

1. Have different accounts for different 'identities' (work, hobby, family/friends)
2. Use twitter for only work and use facebook (or other) for family/friends
3. Have just one twitter account for every aspect of life.

There were well grounded and rounded reasons for each individual's choice, which I will not enlarge on here. What I wanted to highlight was that these routes perplex new users, not least when in the presence of experts discussing the relative merits of their adopted position. This position is not necessarily fixed either, but could shift over the course of a year or years.
Being aware of and able to hold competing conceptions or approaches of use in tension, without it hindering activity is an implicit ability that undergirds the use of social media. I've been through my own digital identity soul searching, eventually deciding to stump for option 3 above. The hiatus was quite disconcerting for a while. Others will wonder what all the fuss was about, yet others will never get to the point of resolving these issues having been switched off by them completely.