The link works now. :)
In Depth Study
The Co-existence Theory
You may or may not have heard of Pearlshipping's flagship song, High Touch. High Touch clearly shows Ash
and Dawn's closeness to each other. This has not featured in any case before. (Misty's song is not a valid argument because it was inserted by the dub 4Kids, which means the song is not canon). Their depiction is this song is borderline romantic, to say the least. It would be certain to say that if another couple existed, this other
girl would be jealous. Also, if another couple existed, along with High Touch, it would give a polygamous & perhaps adulterous impression.
The song High Touch, is simply too implicit for Pearlshipping to allow another ship to co-exist with the song still in existence to come into play.
The Kenny-Serena Theory
There have been many concerns over a new ship in Pokemon known as Amourshipping. Now, Serena has a very obvious crush on Ash, more or less as obvious as Kenny's crush on Dawn. Bad news for Pearlshipping? I think not. It is known that, as said before, Kenny's goodbye in the DP series is very much Dawn letting him down gently for Ash. Ash and Dawn are known to have many parallels-(the way they bonded with their starter Pokemon, their brief period of insecurity)- Kenny and Serena are potentially one of them.
It has also been stated in general anime tradition that childhood friends who have a crush on a main protagonist rarely get their way. Kenny is definitely Dawn's childhood friend. It is disputable as to whether Serena could be described as Ash's childhood friend, their meeting in the anime portrayed very much as a one-time incident, but for the sake of this theory, we will assume that they could be called childhood friends (who is to say that they don't further interact at the summer school?(which would make them childhood friends)). Childhood friends are very much there to make characters notice each other in a romantic light. Judging by the fact that it is likely Ash and Dawn will meet again (See: Farewell, or See You Later?), it is not implausible that this is Serena's role, rather than for her and Ash to become a couple, same with Kenny and Dawn.