Social bookmarking sites such as Delicious and StumbleUpon differ from social news sites such as Reddit and Digg in that:
a. the objective of their users is to collect, save, and share interesting and valuable links.
b. they allow users to edit the stories they find for accuracy.
c. users can change their profiles and update their status whenever they wish.
d. they treat location-based micronetworking as a game.
e. posts are limited to no more than 140 characters in length.
ANSWER: a