Official party platforms mean a great deal. They tell people what the ideals of the party are. That does not mean a certain candiate will not go against the official party platform and make descions that are not in line with the party line, but it gives a guideline for them.
Yes, official party platforms mean something. This is because, it gives order and also gives a sense of belonging. We are able to to identify ourselves with a particular political party. The official party platforms also promotes organization. The public or rather citizens are able to believe that their leader are organized hence can be distinguished.
Official party platforms only mean that in general, the candidate representing the platform is overall on a particular side of the middle line of the political spectrum. A moderate Republican may be more similar to a Democrat candidate than they are to an ultra-Conservative Republican candidate. The platform is only a way to gain a voting base.
No, official party platforms don't seem to mean much. They are a general guideline or suggestion of how a particular group might tend to think. While many party's tout them as an official declaration of how their candidate with act in office, they don't seem to believe it. In practice, they are really an invitation for certain individuals to confidently join the party and vote for those candidates.