Complex sentence: Since then it has grown into a global movement; by April 2003 the website had over 113,000 members, and in 2004 the "Concise Oxford Dictionary" began to include the word "bookcrossing", as defined above.
Split into simpler sentences: Since then it has grown into a global movement: by April 2003 the website had over 113,000 members. In 2004 the "Concise Oxford Dictionary" added the work "bookcrossing", as defined above.