Codes are usually five, six or seven digits in length, mostly starting with 6, 7 or 8. Codes starting 70 are used by charities.<ref>{{cite web|url=http://www.short-codes.com/ |title=Short-Codes.com |publisher=Short-Codes.com |access-date=2011-10-17}}</ref> The range of codes may be expanded in time to use other leading digits such as 4. Adult related mobile services must use codes starting with 69 or 89. Mobile operators sometimes use proprietary codes (either with a different leading digit or shorter in length for their own use). SMS short codes are often owned by holding companies<ref>{{cite web | url=http://www.smsshortcodes.co.uk/shared-and-dedicated-shortcodes.htm |title=A Short Guide to a (UK) Short Code |work=SMSshortcodes.co.uk |date=2009-03-11}}</ref> who then lease them out to service providers and advertisers to promote SMS services, charitable fundraising and marketing promotions such as news alerts, voting and quizzes. Shortcodes can also be used to deliver additional content or a mobile URL link that when prompted opens the mobile web browser linking the user to a mobile web page. Premium SMS services use codes that can be set to deliver a charge to a participant's mobile phone (in accordance with the service provider's terms of service). Other codes (typically used by advertisers) can be free to receive “your(one "standard rate applies”text message charge", applies when sending a message to the number), or free to send and receive. UK Premium rated SMS services are regulated by the [[Phone-paid Services Authority]]. All charges and associated terms linked to a premium code should be transparent to the consumer. To stop a subscription based shortcode service text the word 'STOP' to the shortcode number.
Codes starting 70 are used by charities.<ref name="sc">{{cite web|url=http://www.short-codes.com/ |title=Short-Codes.com |publisher=Short-Codes.com |access-date=2011-10-17}}</ref> Codes starting with 72 are used by Society Lotteries.<ref name="sc" /> Adult related mobile services must use codes starting with 69 or 89. Mobile operators sometimes use proprietary codes (either with a different leading digit, or shorter in length) for operator-specific functions. Depending on the service offered, users may interact with service providers either by calling, sending and/or receiving a text or MMS message. Shortcodes can also be used to deliver additional content or a mobile URL link that when prompted opens the mobile web browser linking the user to a mobile web page.
