I am a big fan of the Micro­for­mats ini­ta­tive. From the site:

Designed for humans first and machines sec­ond, micro­for­mats are a set of sim­ple, open data for­mats built upon exist­ing and widely adopted stan­dards. Instead of throw­ing away what works today, micro­for­mats intend to solve sim­pler prob­lems first by adapt­ing to cur­rent behav­iors and usage pat­terns (e.g. XHTML, blogging).

So essen­tially, the idea is: if you write a review (like I did below), announce an event, post a per­son or job pro­file — do it in a stan­dard­ized way, so it can be reused and aggre­gated. The good thing is that there are lots of edi­tors and read­ers already out there. So for exam­ple you can use the Tails Fire­fox Exten­sion to auto­mat­i­cally add events men­tioned on web pages to your cal­en­dar or save address cards etc. End­less pos­si­bil­i­ties of seam­less data interaction.

I use the Struc­tured Blog­ging Plu­gin for Word­Press to have ready-made forms for post­ing reviews. For the book review, I just entered the title and it grabbed all the meta-data from Ama­zon. Melikes!