Rich Internet Applications, a term coined by Macromedia (now owned by Adobe), is where the whole Web-based user experience is at. At the forefront of RIA technologies you have Adobe AIR, Adobe Flex, Microsoft Silverlight and of course AJAX. Here is a good site for all you UI specialists out there… I’m sure there are more, but I particularly liked this one because of this article.
Anyway here is the link: http://www.uiresourcecenter.com/index.html
The PageRank of a webpage as used by Google is defined by a Markov chain. It is the probability to be at page i in the stationary distribution on the following Markov chain on all (known) webpages. If N is the number of known webpages, and a page i has ki links then it has transition probability 
for all pages that are linked to and 
for all pages that are not linked to. The parameter α is taken to be about 0.85.
Markov models have also been used to analyze web navigation behavior of users. A user’s web link transition on a particular website can be modeled using first- or second-order Markov models and can be used to make predictions regarding future navigation and to personalize the web page for an individual user.
Hmm… more on this later.