tntey
Feel free to call me Griff.
Slipping into psudo-IC mode: (Note, I am not IC, and so I may be trying to mislead you; I will promise that I am not; however, you will have to read what I say and decide if I am for yourself)
At the start of the game, there is no particular reason to assume one person is more guilty than any other; and so his vote obviously didn't say "I think you are the most suspicious person at the moment." His vote however can be used to say "I am giving you my full attention, consider what you say carefully for I can and will be tearing it apart looking for anything remotely suspicious in your answer." This is entirely valid, and quite often recommended, at the beginning of the first day as it allows you to see how that person will act with a little bit of pressure on them, which can be very helpful in getting a read on the person.
Now, this is not the only way to collect these reads; NJW2000 has mentioned his preference for a more laid-back approach of asking more passive questions, which fillipk seems to think is likewise ideal; Frostmoon has brought up striking up conversation, which could bring in reads on people depending on how it is used; I am trying something a bit unusual, but it seems to be working alright for me. It is however a classic way to begin a day, often people will start a day asking a list of questions to various people (all, some, a couple, or just one randomly selected) and voting for one of them as additional pressure.
Do you at this point have any general sense of who might be a townie and who might be mafia? Or even what one particular person might be? Feel free to re-read the thread, thinking about whether people's attitudes, questions, reactions, etc. make more sense if they are acting on their own, or if they know who everyone else is. Possibly look at one particular person, and see how they are acting.