Uask - Uvouch

Uask - Sell or buy for the price you want - Ecommerce

Uberchannel - Create & share your own channel - Video

Ubernote - Access personal to do lists, web clips, research, bookmarks, contacts, and any random notes, anywhere - Office

Ubikuo - Make & share notes - Office

Ubiplanet - Explore, share, discuss & manage your content - Multimedia

Ubroadcast - Host your own live radio show - Audio

Ubu* - Upload, explore & share avant-garde art (since 1996) - Multimedia

Uclue - Q&A - Knowledge

Ucodit - Search code - Software

Udutu - Online course authoring - Publishing

Ufeed - Get RSS feeds in your own page - RSS

Ufem - Blog solution for women - Publishing

Uhuroo - Collaboration tools - Productivity

Uize** - Java API Library - Software

Ujiko** - Visual your search, manipulate results, manage your reputation (by the wizards from Kartoo); the more you use it, the more cool features you get - Search

U-lik - Build your virtual library & share it - Community

Ulinkx - Search, bookmark & share media - Bookmarking

Ulocate - Mobile location based services solutions - Software

Ultrastar - Offer your fans a value add online content experience during your tour - Audio

Umando - Automated IT helpdesk service - VAS

Ummyeah - Digg videos & news - Video

Umundo - Upload & share mobile videos and pics - Multimedia

Unalog - Share what you read, in groups - List

Uncutvideo - AOL's You Tube - Video

Uncyclopedia - Search & contribute to unwiki of nonsense & best taste - Fun

Unfuddle - Ticket, source control & project management - Software

Unicommunity - Comprise or expand your Google results - Search

Uniteddogs - Dog-lovers community - Community

Universalmessengerplus - Meta instant messenger - Communicating

Universe** - Presents search results in stellar clouds - Search

Unizr - Bring up & share your topics - Communicating

Unofficialdb - Search & review mapped restaurants - Ecommerce

Unspun - Publish & share your best-of lists - List

Unwiredbuyer - Voice-based commerce platform - Ecommerce

Unyte - Enterprise instant messaging & web conferencing - Communicating

Upblogger - Make money on your content - Economy

Upcoming - Learn your vocabulary - Ecommerce

Upfordown - Store & share - Storage

Upingme - Classified advertising from your mobile phone - Marketing

Uplayme - Share music & meet people with same taste - Community

Upscoop - Discover which of your friends are on social networks - Community

Upspring - B2B social networking - Community

Upto11 - Discover & share music - Audio

Upwarded - Upload, rank & share multimedia - Storage

Urbandictionary - Contribute to slang dictionary - Office

Urbaniacs - Create your avatar & fight against others - Gaming

Urbanplanet - Discuss urban (USA) issues - Community

Urbis - Community for creative people - Community

Urinfo - Real time website popularity trends - Data

Urladex* - Trade shares in sites (olim Alexadex) - Gaming

Urlex - Leave comments on any website - Bookmarking

Urlfan - Real time blog reference search - Search

Urlx - Shorten your URL - Software

Useamap - Create your own maps with short URLs - Geo

Usebb - Bulletin board solution - Software

Uselessaccount - Impress your friends with your ability to tab through form fields and arrow through saved field values! - Fun

Userplane - Chat, messenger, record - Communicating

Userplanemoney - Rev share-based ad network for the sociosphere (AOL) - Marketing

Userscape - Web-based help desk portal - CRM

Userscripts - Publish, request & comment on scripts - Software

Uship - Auction, or bid for, transportation services - Ecommerce

Ushops - Put up your creative stuff for sale - Ecommerce

Uspot - Upload & share media - Storage

Ustream - Video cast tool - Video

Usuggest - Shop, suggest & make money - Ecommerce

Utensil-ed* - Submit ideas and concepts & brainstorm about them with other users - Productivity

Utterz - Use your mobile to publish your voice, videos, pictures & text on your blog - Publishing

Uvouch - Submit & rate videos - Rating