A secure democratic Net is a fundamental right

They launched (BETA) Highly predictive blacklists that employ a link analysis algorithm similar to Google's PageRank scheme used to find the most relevant web pages given a user's query. But instead of web queries, the firewall logs of DShield contributors are cross-compared with one another in search of overlaps among the attackers they report. The attacker addresses included within a HPB are selected by favoring the inclusion of those attackers who have been encountered by other contributors who share degrees of overlap with the HPB owner

Advice somewhere in your firewall you can make rules that make it possible to monitor something without blocking it. If you want to be sure to use this list without blocking normal websites or services you should do this.

This is how you participate by giving logs just like all these other Belgians did

and these are more important links to use