UBE - Abbreviation for Unsolicited Bulk Email

UCE - Abbreviation for Unsolicited Commercial Email

UK - Abbreviation for United Kingdom

UKOLN - Abbreviation for United Kingdom Office for Library and Information Networking

Underdelivery - The delivery of less impressions, visitors, or conversions than contracted for a specified period of time.

Unethical SEO - The opposite of Ethical SEO, usually involves illegal activities to increase search engine ranking, Unethical SEO practices include cloaking, gateway pages, keyword spamming.

Unique Visitor - The one person that is visiting a website, the one person may generate multiple visits over a period of time and log files show more visits than unique visitors.

Unique User - Same as Unique Visitor.

Uniques - Short for Unique Visitors.

UNIX Hosting - Web hosting that supports UNIX, an operating system that comes in several proprietary versions.

Unlimited Bandwidth - A claim that users of a hosting plan will not be charged extra fees for very high levels of data transfer.

Upload - The process of transferring information from a local drive to a server, specifically when that information then becomes accessible via the Internet.

Uptime Guarantee - An assurance that is a hosting company's uptime will meet an agreed-upon percentage.

URI - Abbreviation for Uniform Resource Indicator

URL - Abbreviation for Uniform Resource Locator / Universal Resource Locator. A unique address that is Internet resource must have in order to be located. Commonly referred to as the domain name, this is how humans navigate through the Internet, whereas computers use IP addresses.

URL Conversion - The method to render dynamic website to appear as static, URLs that contain variable information denoted with "?" and "&"

URL submission - See Submission.

URL Variables - "?", "&" and "%" and other non standard outputs in the URL.

URN - Abbreviation for Uniform Resource Name

USA - Abbreviation for United States of America

Usability - The usability is making website easy for visitors to find the exact information they need, easy, intuitive navigation and strong, informative text enhance usability.

USD - Currency Code for United States Dollars

User Agent - A User Agent is the name of the software accessing a web page.

USP - Abbreviation for Unique Selling Proposition, sometimes mistakenly defined as Unique Selling Point. Basically, it's what sets you apart from your competition. Effective advertising that conforms to certain advertising concepts.

UTC - Abbreviation for Universal Time Coordinated or Coordinated Universal Time