Science Links by Tag
Entrez PubMed - Access to databases which index nucleotide sequences, protein sequences, macromolecular structures, whole genomes, and MedLine.
Nucleic Acids Research Molecular Biology Database Collection - A public resource with links to molecular biology databases that are freely available on the web.
JoVE - Journal of Visualized Experiments, video demonstrations of experiments
This is an example of what tags can look like from the social bookmarking site delicious.