I am building a site using Serverside JAVA (JSP,classes and Servlets). I have built the content management/dynamic content part from scratch, but now I have asked to add personalization and user tracking. What is the best: to built this from scratch too or to use a tool that provides that? Which tools can provide this, I don't want to loose the developed code. Does any Application Server provides this? how? where to find details?
I assume that by now, probably all the big vendors support personalization in some way. I know for sure BEA and IBM have solutions for this (under the label "personalization server" or some variation of that). You might also want to take a look at ATG's Dynamo, which is rumored to be particularly strong in this area.
It still depends on your users' demands, though, whether one of these expensive solutions is justified - if their demands are not too high, you can probably come up with something yourself.