The colon has two major uses:
- to introduce a list (as here)
- to separate two parts of a sentence, where the second part provides more information on or clarifies the first.
Colons should never be followed by a hyphen, and the first word that follows the colon is not capitalised in British English.
Examples of lists are:
- There are many new technologies: MP3s, DiVX, almost universal broadband internet, P2P networks and many developments in telephony.
- Colons have many uses: to introduce lists; to separate two parts of sentence; to introduce quotations; when writing ratios; and when citing passages from journals.
Examples of where a colon leads to more detail include:
- The scale of illicit file-sharing is a problem for the music industry: £414 million in lost sales in 2005 alone.
and when introducing a piece of direct speech or a quotation:
- In his paper on the internet and society, Al Gore was clear: 'Global Information Infrastructure (GII) will spread participatory democracy.'2