This page displays the number of entries (articles) in PubMed (Medline) published every year, that conform to search strategy (such as a phrase) you enter.
Quarkbase is a free tool to find complete information about a website. It is a mashup of over 30 data sources and many algorithms gathering information from Internet on various topics like social popularity, traffic, associated people, etc. e.g. http://www.quarkbase.com/show/microbiologybytes.com