This isn't a dating question, it's a general purpose question that also applies to dating:
If you call, and don't get an answer, you can:
- leave a voice message – putting the ball in the other person's court,
- leave a text message – putting the ball in the other person's court,
- (where applicable) send an email/IM/tweet/FB message – putting the ball in the other person's court,
- keep calling until you get them – giving them no responsibility in getting back to you (assuming they screen calls)
Doing any one of the above is perfectly acceptable these days, though different women (or men for that matter) will have different preferred modes of contact.
As numerous other answerers have mentioned, calling in the context of dating is a good thing, generally. Leaving a message may or may not be desired, but in and of itself won't paint you in a negative light (unless you have very bad messaging skills: http://melodymaker.posterous.com… ).
No, the main problem is not the call, or the message, it's in expecting a timely response. Given the amazing crush of work, school, family, and friends, even the best intentioned potential date simply may not be able to get back to you very quickly. And, more importantly, if all you're working off of is a good conversation in a bar and a phone number, perhaps consider trying to replicate that experience 9 more times – a 10% call back rate should be seen as a success these days, and the more numbers you get, the more potential good dates that 10% will represent.
In contrast, if you repeatedly call the same person over and over, because getting even that single number seems like a big deal to you, then you'll either be 100% successful, or 100% failure… And the creepy persistence angle definitely leans more in favor of one of those options.
In short, when you call, leave some kind of message, because:
- it gives the other party control over how and when to respond – which you can then use to help gauge their interest in you;
- it gives them less latitude to claim that they didn't receive your call;
- it allows you to make a move, and help vent some of the excitement/energy at meeting someone new, and move on with your day
Note that last part: and move on with your day. Do not call back a second time, or a twentieth. The phone companies don't suck that much(*), and it's not helping your case to be 14 of her 16 missed calls.
And a brief note to call screeners – if someone puts in some effort to get to know you better, take it as a compliment. When possible, do try to reciprocate, even in rejection… It makes you bolder and more interesting/classy if done politely, and while it may initially sting the caller, they will be far less hurt and/or confused than the ones who seemed to hit it off with you and never hear back.
(* Okay, I lied, they do suck, a lot, but just not typically in terms of losing call logs/voicemails/etc)