I keep seeing posts that state that Puerto Rico is winner take all, however that is not the case. In the Presidential Primaries, PR is allotted a fixed number of delegates, that are split proportionately.
The pledged delegates are allocated among the states according to two main criteria: 1) proportion of votes each state gave the candidate in the last three Presidential elections; and 2) percentage of votes each state has in the Electoral College. Fixed numbers of delegates are allocated for Puerto Rico, American Samoa, Guam, the U.S. Virgin Islands, and Democrats Abroad. Under the party's Delegate Selection Rules for the 2008 Democratic National Convention<7>, delegates are awarded via proportional representation with a minimum threshold of 15% of votes in a state or congressional district to receive delegates. The delegate population must reflect the state's ethnic distribution; and at least 50% of the delegates must be women.
http://en.wikipedia.org/wiki/2008_Democratic_National_Convention