I had the same question a couple weeks ago. Somehow to me it seemed rude to have more than one comminucation going, but rude to whom? Realistically speaking, those people you are communicating with are probably also communicating with at least one other so my answer is this, the more communications you open the better chances you have at meeting the right one for you. Probably no more than three though or it would really get confusing. You will find as you go along, that often times some people close you mid communication while others just plain dissapear, so better to really review your matches and go for it. : )